The economics of HIV vaccines - Projecting the impact of HIV vaccination of infants in sub-Saharan Africa

NARCIS (Netherlands)

Bos, JM; Postma, MJ

2001-01-01

Objectives: (i) To project vaccine parameters, economic consequences and market size associated with HIV-1 vaccination of infants in sub-Saharan Africa through the Expanded Program on Immunisation (EPI); and (ii) to assess threshold values for price and effectiveness. Study design and methods:

Architectural Insight into Inovirus-Associated Vectors (IAVs and Development of IAV-Based Vaccines Inducing Humoral and Cellular Responses: Implications in HIV-1 Vaccines

Directory of Open Access Journals (Sweden)

Kyriakos A. Hassapis

2014-12-01

Full Text Available Inovirus-associated vectors (IAVs are engineered, non-lytic, filamentous bacteriophages that are assembled primarily from thousands of copies of the major coat protein gp8 and just five copies of each of the four minor coat proteins gp3, gp6, gp7 and gp9. Inovirus display studies have shown that the architecture of inoviruses makes all coat proteins of the inoviral particle accessible to the outside. This particular feature of IAVs allows foreign antigenic peptides to be displayed on the outer surface of the virion fused to its coat proteins and for more than two decades has been exploited in many applications including antibody or peptide display libraries, drug design, and vaccine development against infectious and non-infectious diseases. As vaccine carriers, IAVs have been shown to elicit both a cellular and humoral response against various pathogens through the display of antibody epitopes on their coat proteins. Despite their high immunogenicity, the goal of developing an effective vaccine against HIV-1 has not yet materialized. One possible limitation of previous efforts was the use of broadly neutralizing antibodies, which exhibited autoreactivity properties. In the past five years, however, new, more potent broadly neutralizing antibodies that do not exhibit autoreactivity properties have been isolated from HIV-1 infected individuals, suggesting that vaccination strategies aimed at producing such broadly neutralizing antibodies may confer protection against infection. The utilization of these new, broadly neutralizing antibodies in combination with the architectural traits of IAVs have driven the current developments in the design of an inovirus-based vaccine against HIV-1. This article reviews the applications of IAVs in vaccine development, with particular emphasis on the design of inoviral-based vaccines against HIV-1.

Understanding HIV infection for the design of a therapeutic vaccine. Part II: Vaccination strategies for HIV.

Science.gov (United States)

de Goede, A L; Vulto, A G; Osterhaus, A D M E; Gruters, R A

2015-05-01

HIV infection leads to a gradual loss CD4(+) T lymphocytes comprising immune competence and progression to AIDS. Effective treatment with combined antiretroviral drugs (cART) decreases viral load below detectable levels but is not able to eliminate the virus from the body. The success of cART is frustrated by the requirement of expensive lifelong adherence, accumulating drug toxicities and chronic immune activation resulting in increased risk of several non-AIDS disorders, even when viral replication is suppressed. Therefore, there is a strong need for therapeutic strategies as an alternative to cART. Immunotherapy, or therapeutic vaccination, aims to increase existing immune responses against HIV or induce de novo immune responses. These immune responses should provide a functional cure by controlling viral replication and preventing disease progression in the absence of cART. The key difficulty in the development of an HIV vaccine is our ignorance of the immune responses that control of viral replication, and thus how these responses can be elicited and how they can be monitored. Part one of this review provides an extensive overview of the (patho-) physiology of HIV infection. It describes the structure and replication cycle of HIV, the epidemiology and pathogenesis of HIV infection and the innate and adaptive immune responses against HIV. Part two of this review discusses therapeutic options for HIV. Prevention modalities and antiretroviral therapy are briefly touched upon, after which an extensive overview on vaccination strategies for HIV is provided, including the choice of immunogens and delivery strategies. Copyright © 2014. Published by Elsevier Masson SAS.

Therapeutic Vaccination Using Cationic Liposome-Adjuvanted HIV Type 1 Peptides Representing HLA-Supertype-Restricted Subdominant T Cell Epitopes

DEFF Research Database (Denmark)

Román, Victor Raúl Gómez; Jensen, Kristoffer Jarlov; Jensen, Sanne Skov

2013-01-01

We have designed a therapeutic HIV-1 vaccine concept based on peptides together with the adjuvant CAF01. Peptides represented 15 HLA-supertype-restricted subdominant and conserved CD8 T cell epitopes and three CD4 T-helper cell epitopes. In this phase I clinical trial, safety and immunogenicity...... were assessed in untreated HIV-1-infected individuals in Guinea-Bissau, West Africa. Twenty-three HIV-1-infected individuals were randomized to receive placebo (n=5) or vaccine (n=18). Safety was appraised by clinical follow-up combined with monitoring of biochemistry, hematology, CD4 T cell counts......, and HIV-1 viral loads. T cell immunogenicity was monitored longitudinally by interferon (IFN)-γ ELISpot. New vaccine-specific T cell responses were induced in 6/14 vaccinees for whom ELISpot data were valid. CD4 T cell counts and viral loads were stable. The study shows that therapeutic immunization...

The multi-epitope polypeptide approach in HIV-1 vaccine development.

Science.gov (United States)

Cano, C A

1999-11-01

The application of a preventive HIV vaccine is the only hope for most developing countries to halt the AIDS pandemic. A project aimed to develop a preventive AIDS vaccine is being carried out since 1992 by three Cuban research institutions: Centro de Ingeniería Genética y Biotecnologia de La Habana, Instituto de Medicina Tropical 'Pedro Kouri' and Laboratorio de Investigaciones de SIDA de La Habana. The project includes two main strategies: (a) generation of recombinant multi-epitope polypeptides (MEPs) bearing several copies of the V3 loop from different HIV-1 isolates; and (b) development of immunogens capable of inducing a cytotoxic T cell response (CTL) specific for human immunodeficiency virus type 1 (HIV-1) antigens. This article summarizes the work in the first of these strategies. Based on the sequence of the V3 loop of HIV-1 we constructed a series of MEPs and evaluated their immunogenicity in mice, rabbits and macaques. The MEP TAB9, containing six V3 epitopes from isolates LR10, JY1, RF, MN, BRVA and IIIB, was selected together with the oil adjuvant Montanide ISA720 (SEPPIC, France) to perform a Phase I clinical trial in HIV seronegative Cuban volunteers. The trial was double blinded, randomized, and fulfilled all ethical and regulatory requirements. All TAB9 vaccinated volunteers developed a strong immune response and neutralizing antibodies were observed in the 50% of the subjects. However the second and third inoculations of the vaccine were not well tolerated because transient severe local reactions appeared in some individuals. A new formulation of TAB9 is currently in pre-clinical studies and is expected to enter clinical trials in 1999.

Biologic interactions between HSV-2 and HIV-1 and possible implications for HSV vaccine development.

Science.gov (United States)

Schiffer, Joshua T; Gottlieb, Sami L

2017-09-25

Development of a safe and effective vaccine against herpes simplex virus type 2 (HSV-2) has the potential to limit the global burden of HSV-2 infection and disease, including genital ulcer disease and neonatal herpes, and is a global sexual and reproductive health priority. Another important potential benefit of an HSV-2 vaccine would be to decrease HIV infections, as HSV-2 increases the risk of HIV-1 acquisition several-fold. Acute and chronic HSV-2 infection creates ulcerations and draws dendritic cells and activated CD4+ T cells into genital mucosa. These cells are targets for HIV entry and replication. Prophylactic HSV-2 vaccines (to prevent infection) and therapeutic vaccines (to modify or treat existing infections) are currently under development. By preventing or modifying infection, an effective HSV-2 vaccine could limit HSV-associated genital mucosal inflammation and thus HIV risk. However, a vaccine might have competing effects on HIV risk depending on its mechanism of action and cell populations generated in the genital mucosa. In this article, we review biologic interactions between HSV-2 and HIV-1, consider HSV-2 vaccine development in the context of HIV risk, and discuss implications and research needs for future HSV vaccine development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determinants of vaccine immunogenicity in HIV-infected pregnant women: analysis of B and T cell responses to pandemic H1N1 monovalent vaccine.

Directory of Open Access Journals (Sweden)

Adriana Weinberg

Full Text Available Influenza infections have high frequency and morbidity in HIV-infected pregnant women, underscoring the importance of vaccine-conferred protection. To identify the factors that determine vaccine immunogenicity in this group, we characterized the relationship of B- and T-cell responses to pandemic H1N1 (pH1N1 vaccine with HIV-associated immunologic and virologic characteristics. pH1N1 and seasonal-H1N1 (sH1N1 antibodies were measured in 119 HIV-infected pregnant women after two double-strength pH1N1 vaccine doses. pH1N1-IgG and IgA B-cell FluoroSpot, pH1N1- and sH1N1-interferon γ (IFNγ and granzyme B (GrB T-cell FluoroSpot, and flow cytometric characterization of B- and T-cell subsets were performed in 57 subjects. pH1N1-antibodies increased after vaccination, but less than previously described in healthy adults. pH1N1-IgG memory B cells (Bmem increased, IFNγ-effector T-cells (Teff decreased, and IgA Bmem and GrB Teff did not change. pH1N1-antibodies and Teff were significantly correlated with each other and with sH1N1-HAI and Teff, respectively, before and after vaccination. pH1N1-antibody responses to the vaccine significantly increased with high proportions of CD4+, low CD8+ and low CD8+HLADR+CD38+ activated (Tact cells. pH1N1-IgG Bmem responses increased with high proportions of CD19+CD27+CD21- activated B cells (Bact, high CD8+CD39+ regulatory T cells (Treg, and low CD19+CD27-CD21- exhausted B cells (Bexhaust. IFNγ-Teff responses increased with low HIV plasma RNA, CD8+HLADR+CD38+ Tact, CD4+FoxP3+ Treg and CD19+IL10+ Breg. In conclusion, pre-existing antibody and Teff responses to sH1N1 were associated with increased responses to pH1N1 vaccination in HIV-infected pregnant women suggesting an important role for heterosubtypic immunologic memory. High CD4+% T cells were associated with increased, whereas high HIV replication, Tact and Bexhaust were associated with decreased vaccine immunogenicity. High Treg increased antibody responses but

Development of a Preventive HIV Vaccine Requires Solving Inverse Problems Which Is Unattainable by Rational Vaccine Design

Directory of Open Access Journals (Sweden)

Marc H. V. Van Regenmortel

2018-01-01

Full Text Available Hypotheses and theories are essential constituents of the scientific method. Many vaccinologists are unaware that the problems they try to solve are mostly inverse problems that consist in imagining what could bring about a desired outcome. An inverse problem starts with the result and tries to guess what are the multiple causes that could have produced it. Compared to the usual direct scientific problems that start with the causes and derive or calculate the results using deductive reasoning and known mechanisms, solving an inverse problem uses a less reliable inductive approach and requires the development of a theoretical model that may have different solutions or none at all. Unsuccessful attempts to solve inverse problems in HIV vaccinology by reductionist methods, systems biology and structure-based reverse vaccinology are described. The popular strategy known as rational vaccine design is unable to solve the multiple inverse problems faced by HIV vaccine developers. The term “rational” is derived from “rational drug design” which uses the 3D structure of a biological target for designing molecules that will selectively bind to it and inhibit its biological activity. In vaccine design, however, the word “rational” simply means that the investigator is concentrating on parts of the system for which molecular information is available. The economist and Nobel laureate Herbert Simon introduced the concept of “bounded rationality” to explain why the complexity of the world economic system makes it impossible, for instance, to predict an event like the financial crash of 2007–2008. Humans always operate under unavoidable constraints such as insufficient information, a limited capacity to process huge amounts of data and a limited amount of time available to reach a decision. Such limitations always prevent us from achieving the complete understanding and optimization of a complex system that would be needed to achieve a truly

Motivators of enrolment in HIV vaccine trials: a review of HIV vaccine preparedness studies.

Science.gov (United States)

Dhalla, Shayesta; Poole, Gary

2011-11-01

HIV vaccine preparedness studies (VPS) are important precursors to HIV vaccine trials. As well, they contribute to an understanding of motivators and barriers for participation in hypothetical HIV vaccine trials. Motivators can take the form of altruism and a desire for social benefits. Perceived personal benefits, including psychological, personal, and financial well-being, may also motivate participation. The authors performed a systematic review of HIV VPS using the Cochrane Database for Systematic Reviews, Medline, PubMed, Embase, and Google Scholar. The authors independently searched the literature for individual HIV VPS that examined motivators of participation in a hypothetical HIV vaccine trial, using the same search strategy. As the denominators employed in the literature varied across studies, the denominators were standardized to the number of respondents per survey item, regardless of their willingness to participate (WTP) in an HIV vaccine trial. The authors retrieved eight studies on social benefits (i.e., altruism) and 11 studies on personal benefits conducted in the Organization for Economic Co-operation and Development (OECD) countries, as well as 19 studies on social benefits and 20 studies on personal benefits in the non-OECD countries. Various different forms of altruism were found to be the major motivators for participation in an HIV vaccine trial in both the OECD and the non-OECD countries. In a large number of studies, protection from HIV was cited as a personal motivator for participation in a hypothetical HIV vaccine trial in the OECD and the non-OECD countries. Knowledge of motivators can inform and target recruitment for HIV vaccine trials, although it must be remembered that hypothetical motivators may not always translate into motivators in an actual vaccine trial.

Live attenuated measles vaccine expressing HIV-1 Gag virus like particles covered with gp160ΔV1V2 is strongly immunogenic

International Nuclear Information System (INIS)

Guerbois, Mathilde; Moris, Arnaud; Combredet, Chantal; Najburg, Valerie; Ruffie, Claude; Fevrier, Michele; Cayet, Nadege; Brandler, Samantha; Schwartz, Olivier; Tangy, Frederic

2009-01-01

Although a live attenuated HIV vaccine is not currently considered for safety reasons, a strategy inducing both T cells and neutralizing antibodies to native assembled HIV-1 particles expressed by a replicating virus might mimic the advantageous characteristics of live attenuated vaccine. To this aim, we generated a live attenuated recombinant measles vaccine expressing HIV-1 Gag virus-like particles (VLPs) covered with gp160ΔV1V2 Env protein. The measles-HIV virus replicated efficiently in cell culture and induced the intense budding of HIV particles covered with Env. In mice sensitive to MV infection, this recombinant vaccine stimulated high levels of cellular and humoral immunity to both MV and HIV with neutralizing activity. The measles-HIV virus infected human professional antigen-presenting cells, such as dendritic cells and B cells, and induced efficient presentation of HIV-1 epitopes and subsequent activation of human HIV-1 Gag-specific T cell clones. This candidate vaccine will be next tested in non-human primates. As a pediatric vaccine, it might protect children and adolescents simultaneously from measles and HIV.

Combining biomedical preventions for HIV: Vaccines with pre-exposure prophylaxis, microbicides or other HIV preventions.

Science.gov (United States)

McNicholl, Janet M

2016-12-01

Biomedical preventions for HIV, such as vaccines, microbicides or pre-exposure prophylaxis (PrEP) with antiretroviral drugs, can each only partially prevent HIV-1 infection in most human trials. Oral PrEP is now FDA approved for HIV-prevention in high risk groups, but partial adherence reduces efficacy. If combined as biomedical preventions (CBP) an HIV vaccine could provide protection when PrEP adherence is low and PrEP could prevent vaccine breakthroughs. Other types of PrEP or microbicides may also be partially protective. When licensed, first generation HIV vaccines are likely to be partially effective. Individuals at risk for HIV may receive an HIV vaccine combined with other biomedical preventions, in series or in parallel, in clinical trials or as part of standard of care, with the goal of maximally increasing HIV prevention. In human studies, it is challenging to determine which preventions are best combined, how they interact and how effective they are. Animal models can determine CBP efficacy, whether additive or synergistic, the efficacy of different products and combinations, dose, timing and mechanisms. CBP studies in macaques have shown that partially or minimally effective candidate HIV vaccines combined with partially effective oral PrEP, vaginal PrEP or microbicide generally provided greater protection than either prevention alone against SIV or SHIV challenges. Since human CBP trials will be complex, animal models can guide their design, sample size, endpoints, correlates and surrogates of protection. This review focuses on animal studies and human models of CBP and discusses implications for HIV prevention.

HIV-1-Specific IgA Monoclonal Antibodies from an HIV-1 Vaccinee Mediate Galactosylceramide Blocking and Phagocytosis

Science.gov (United States)

2018-01-01

ABSTRACT Vaccine-elicited humoral immune responses comprise an array of antibody forms and specificities, with only a fraction contributing to protective host immunity. Elucidation of antibody effector functions responsible for protective immunity against human immunodeficiency virus type 1 (HIV-1) acquisition is a major goal for the HIV-1 vaccine field. Immunoglobulin A (IgA) is an important part of the host defense against pathogens; however, little is known about the role of vaccine-elicited IgA and its capacity to mediate antiviral functions. To identify the antiviral functions of HIV-1-specific IgA elicited by vaccination, we cloned HIV-1 envelope-specific IgA monoclonal antibodies (MAbs) by memory B cell cultures from peripheral blood mononuclear cells from an RV144 vaccinee and produced two IgA clonal cell lines (HG129 and HG130) producing native, nonrecombinant IgA MAbs. The HG129 and HG130 MAbs mediated phagocytosis by monocytes, and HG129 blocked HIV-1 Env glycoprotein binding to galactosylceramide, an alternative HIV-1 receptor. These findings elucidate potential antiviral functions of vaccine-elicited HIV-1 envelope-specific IgA that may act to block HIV-1 acquisition at the portal of entry by preventing HIV-1 binding to galactosylceramide and mediating antibody Fc receptor-mediated virion phagocytosis. Furthermore, these findings highlight the complex and diverse interactions of vaccine-elicited IgA with pathogens that depend on IgA fine specificity and form (e.g., multimeric or monomeric) in the systemic circulation and mucosal compartments. IMPORTANCE Host-pathogen interactions in vivo involve numerous immune mechanisms that can lead to pathogen clearance. Understanding the nature of antiviral immune mechanisms can inform the design of efficacious HIV-1 vaccine strategies. Evidence suggests that both neutralizing and nonneutralizing antibodies can mediate some protection against HIV in animal models. Although numerous studies have characterized the

Induction of immunity to human immunodeficiency virus type-1 by vaccination.

Science.gov (United States)

McElrath, M Juliana; Haynes, Barton F

2010-10-29

Recent findings have brought optimism that development of a successful human immunodeficiency virus type-1 (HIV-1) vaccine lies within reach. Studies of early events in HIV-1 infection have revealed when and where HIV-1 is potentially vulnerable to vaccine-targeted immune responses. With technical advances in human antibody production, clues about how antibodies recognize HIV-1 envelope proteins have uncovered new targets for immunogen design. A recent vaccine regimen has shown modest efficacy against HIV-1 acquisition. However, inducing long-term T and B cell memory and coping with HIV-1 diversity remain high priorities. Mediators of innate immunity may play pivotal roles in blocking infection and shaping immunity; vaccine strategies to capture these activities are under investigation. Challenges remain in integrating basic, preclinical and clinical research to improve predictions of types of immunity associated with vaccine efficacy, to apply these insights to immunogen design, and to accelerate evaluation of vaccine efficacy in persons at-risk for infection. Copyright © 2010 Elsevier Inc. All rights reserved.

Approaches to Preventative and Therapeutic HIV vaccines

Science.gov (United States)

Gray, Glenda E.; Laher, Fatima; Lazarus, Erica; Ensoli, Barbara; Corey, Lawrence

2016-01-01

Novel strategies are being researched to discover vaccines to prevent and treat HIV-1. Nonefficacious preventative vaccine approaches include bivalent recombinant gp120 alone, HIV gene insertion into an Adenovirus 5 (Ad5) virus vector and the DNA prime/Ad5 boost vaccine regimen. However, the ALVAC-HIV prime/AIDSVAX® B/E gp120 boost regimen showed 31.2% efficacy at 3.5 years, and is being investigated as clade C constructs with an additional boost. Likewise, although multiple therapeutic vaccines have failed in the past, in a non-placebo controlled trial, a Tat vaccine demonstrated immune cell restoration, reduction of immune activation, and reduced HIV-1 DNA viral load. Monoclonal antibodies for passive immunization or treatment show promise, with VRC01 entering advanced clinical trials. PMID:26985884

Safety and immunogenicity of therapeutic DNA vaccination in individuals treated with antiretroviral therapy during acute/early HIV-1 infection.

Directory of Open Access Journals (Sweden)

Eric S Rosenberg

2010-05-01

Full Text Available An effective therapeutic vaccine that could augment immune control of HIV-1 replication may abrogate or delay the need for antiretroviral therapy. AIDS Clinical Trials Group (ACTG A5187 was a phase I/II, randomized, placebo-controlled, double-blinded trial to evaluate the safety and immunogenicity of an HIV-1 DNA vaccine (VRC-HVDNA 009-00-VP in subjects treated with antiretroviral therapy during acute/early HIV-1 infection. (clinicaltrials.gov NCT00125099Twenty healthy HIV-1 infected subjects who were treated with antiretroviral therapy during acute/early HIV-1 infection and had HIV-1 RNA<50 copies/mL were randomized to receive either vaccine or placebo. The objectives of this study were to evaluate the safety and immunogenicity of the vaccine. Following vaccination, subjects interrupted antiretroviral treatment, and set-point HIV-1 viral loads and CD4 T cell counts were determined 17-23 weeks after treatment discontinuation.Twenty subjects received all scheduled vaccinations and discontinued antiretroviral therapy at week 30. No subject met a primary safety endpoint. No evidence of differences in immunogenicity were detected in subjects receiving vaccine versus placebo. There were also no significant differences in set-point HIV-1 viral loads or CD4 T cell counts following treatment discontinuation. Median set-point HIV-1 viral loads after treatment discontinuation in vaccine and placebo recipients were 3.5 and 3.7 log(10 HIV-1 RNA copies/mL, respectively.The HIV-1 DNA vaccine (VRC-HIVDNA 009-00-VP was safe but poorly immunogenic in subjects treated with antiretroviral therapy during acute/early HIV-1 infection. Viral set-points were similar between vaccine and placebo recipients following treatment interruption. However, median viral load set-points in both groups were lower than in historical controls, suggesting a possible role for antiretroviral therapy in persons with acute or early HIV-1 infection and supporting the safety of

In "Step" with HIV Vaccines? A Content Analysis of Local Recruitment Campaigns for an International HIV Vaccine Study.

Science.gov (United States)

Frew, Paula M; Macias, Wendy; Chan, Kayshin; Harding, Ashley C

2009-01-01

During the past two decades of the HIV/AIDS pandemic, several recruitment campaigns were designed to generate community involvement in preventive HIV vaccine clinical trials. These efforts utilized a blend of advertising and marketing strategies mixed with public relations and community education approaches to attract potential study participants to clinical trials (integrated marketing communications). Although more than 30,000 persons worldwide have participated in preventive HIV vaccine studies, no systematic analysis of recruitment campaigns exists. This content analysis study was conducted to examine several United States and Canadian recruitment campaigns for one of the largest-scale HIV vaccine trials to date (the "Step Study"). This study examined persuasive features consistent with the Elaboration Likelihood Model (ELM) including message content, personal relevance of HIV/AIDS and vaccine research, intended audiences, information sources, and other contextual features. The results indicated variation in messages and communication approaches with gay men more exclusively targeted in these regions. Racial/ethnic representations also differed by campaign. Most of the materials promote affective evaluation of the information through heuristic cueing. Implications for subsequent campaigns and research directions are discussed.

Dendritic cells exposed to MVA-based HIV-1 vaccine induce highly functional HIV-1-specific CD8(+ T cell responses in HIV-1-infected individuals.

Directory of Open Access Journals (Sweden)

Núria Climent

Full Text Available Currently, MVA virus vectors carrying HIV-1 genes are being developed as HIV-1/AIDS prophylactic/therapeutic vaccines. Nevertheless, little is known about the impact of these vectors on human dendritic cells (DC and their capacity to present HIV-1 antigens to human HIV-specific T cells. This study aimed to characterize the interaction of MVA and MVA expressing the HIV-1 genes Env-Gag-Pol-Nef of clade B (referred to as MVA-B in human monocyte-derived dendritic cells (MDDC and the subsequent processes of HIV-1 antigen presentation and activation of memory HIV-1-specific T lymphocytes. For these purposes, we performed ex vivo assays with MDDC and autologous lymphocytes from asymptomatic HIV-infected patients. Infection of MDDC with MVA-B or MVA, at the optimal dose of 0.3 PFU/MDDC, induced by itself a moderate degree of maturation of MDDC, involving secretion of cytokines and chemokines (IL1-ra, IL-7, TNF-α, IL-6, IL-12, IL-15, IL-8, MCP-1, MIP-1α, MIP-1β, RANTES, IP-10, MIG, and IFN-α. MDDC infected with MVA or MVA-B and following a period of 48 h or 72 h of maturation were able to migrate toward CCL19 or CCL21 chemokine gradients. MVA-B infection induced apoptosis of the infected cells and the resulting apoptotic bodies were engulfed by the uninfected MDDC, which cross-presented HIV-1 antigens to autologous CD8(+ T lymphocytes. MVA-B-infected MDDC co-cultured with autologous T lymphocytes induced a highly functional HIV-specific CD8(+ T cell response including proliferation, secretion of IFN-γ, IL-2, TNF-α, MIP-1β, MIP-1α, RANTES and IL-6, and strong cytotoxic activity against autologous HIV-1-infected CD4(+ T lymphocytes. These results evidence the adjuvant role of the vector itself (MVA and support the clinical development of prophylactic and therapeutic anti-HIV vaccines based on MVA-B.

Differences in HIV vaccine acceptability between genders

Science.gov (United States)

Kakinami, Lisa; Newman, Peter A.; Lee, Sung-Jae; Duan, Naihua

2010-01-01

The development of safe and efficacious preventive HIV vaccines offers the best long-term hope of controlling the AIDS pandemic. Nevertheless, suboptimal uptake of safe and efficacious vaccines that already exist suggest that HIV vaccine acceptability cannot be assumed, particularly among communities most vulnerable to HIV. The present study aimed to identify barriers and motivators to future HIV vaccine acceptability among low socioeconomic, ethnically diverse men and women in Los Angeles County. Participants completed a cross-sectional survey assessing their attitudes and beliefs regarding future HIV vaccines. Hypothetical HIV vaccine scenarios were administered to determine HIV vaccine acceptability. Two-sided t-tests were performed, stratified by gender, to examine the association between vaccine acceptability and potential barriers and motivators. Barriers to HIV vaccine acceptability differed between men and women. For women, barriers to HIV vaccine acceptability were related to their intimate relationships (p Motivators for women included the ability to conceive a child without worrying about contracting HIV (p Motivators for men included feeling safer with sex partners (p motivator for both men and women (p <0.10). Gender-specific interventions may increase vaccine acceptability among men and women at elevated risk for HIV infection. Among women, interventions need to focus on addressing barriers due to gendered power dynamics in relationships and discrimination in health care. Among men, education that addresses fears and misconceptions about adverse effects of HIV vaccination on health and the importance of vaccination as one component of integrated HIV prevention may increase vaccine acceptability. PMID:18484322

HIV-1 Immunogen: an overview of almost 30 years of clinical testing of a candidate therapeutic vaccine.

Science.gov (United States)

Graziani, Gina M; Angel, Jonathan B

2016-07-01

Although current antiretroviral therapy (ART) has transformed HIV infection into a chronic, manageable disease, ART does not cure HIV infection. Furthermore, the majority of the world's infected individuals live in resource-limited countries in which access to ART is limited. Thus, the development of an effective therapeutic HIV vaccine would be an invaluable treatment alternative. Developed by the late Dr. Jonas Salk, HIV-1 Immunogen (Remune®) is a candidate therapeutic vaccine that has been studied in thousands of HIV-infected individuals in more than a dozen clinical trials during almost three decades. This Drug Evaluation, which summarizes the results of these trials that have shown the vaccine to be safe and immunogenic, also discusses the contradictory and controversial conclusions drawn from the phases 2, 2/3 and 3 trials that assessed the clinical efficacy of this vaccine. Given the lack of unequivocal clinical benefits of HIV-1 Immunogen despite almost 30 years of extensive testing, it does not appear, in our view, that this vaccine is a clinically effective immunotherapy. However, inclusion of this vaccine in the newly proposed 'Kick/Shock and Kill' strategy for HIV eradication, or use as a prophylactic vaccine, could be considered for future trials.

HIV vaccines: new frontiers in vaccine development.

Science.gov (United States)

Duerr, Ann; Wasserheit, Judith N; Corey, Lawrence

2006-08-15

A human immunodeficiency virus (HIV) vaccine is the most promising and feasible strategy to prevent the events during acute infection that simultaneously set the course of the epidemic in the community and the course of the disease for the individual. Because safety concerns limit the use of live, attenuated HIV and inactivated HIV, a variety of alternate approaches is being investigated. Traditional antibody-mediated approaches using recombinant HIV envelope proteins have shown no efficacy in 2 phase III trials. Current HIV vaccine trials are focusing primarily on cytotoxic T lymphocyte-mediated products that use viral vectors, either alone or as boosts to DNA plasmids that contain viral genes. The most immunogenic of these products appear to be the recombinant adenovirus vector vaccines, 2 of which are now in advanced clinical development.

Heterologous prime-boost vaccination with DNA and MVA vaccines, expressing HIV-1 subtype C mosaic Gag virus-like particles, is highly immunogenic in mice.

Directory of Open Access Journals (Sweden)

Ros Chapman

Full Text Available In an effort to make affordable vaccines suitable for the regions most affected by HIV-1, we have constructed stable vaccines that express an HIV-1 subtype C mosaic Gag immunogen (BCG-GagM, MVA-GagM and DNA-GagM. Mosaic immunogens have been designed to address the tremendous diversity of this virus. Here we have shown that GagM buds from cells infected and transfected with MVA-GagM and DNA-GagM respectively and forms virus-like particles. Previously we showed that a BCG-GagM prime MVA-GagM boost generated strong cellular immune responses in mice. In this study immune responses to the DNA-GagM and MVA-GagM vaccines were evaluated in homologous and heterologous prime-boost vaccinations. The DNA homologous prime boost vaccination elicited predominantly CD8+ T cells while the homologous MVA vaccination induced predominantly CD4+ T cells. A heterologous DNA-GagM prime MVA-GagM boost induced strong, more balanced Gag CD8+ and CD4+ T cell responses and that were predominantly of an effector memory phenotype. The immunogenicity of the mosaic Gag (GagM was compared to a naturally occurring subtype C Gag (GagN using a DNA homologous vaccination regimen. DNA-GagN expresses a natural Gag with a sequence that was closest to the consensus sequence of subtype C viruses sampled in South Africa. DNA-GagM homologous vaccination induced cumulative HIV-1 Gag-specific IFN-γ ELISPOT responses that were 6.5-fold higher than those induced by the DNA-GagN vaccination. Similarly, DNA-GagM vaccination generated 7-fold higher levels of cytokine-positive CD8+ T cells than DNA-GagN, indicating that this subtype C mosaic Gag elicits far more potent immune responses than a consensus-type Gag. Cells transfected and infected with DNA-GagM and MVA-GagM respectively, expressed high levels of GagM and produced budding virus-like particles. Our data indicates that a heterologous prime boost regimen using DNA and MVA vaccines expressing HIV-1 subtype C mosaic Gag is highly

Relationship of HIV Reservoir Characteristics with Immune Status and Viral Rebound Kinetics in an HIV Therapeutic Vaccine Study

Science.gov (United States)

Li, Jonathan Z.; Heisey, Andrea; Ahmed, Hayat; Wang, Hongying; Zheng, Lu; Carrington, Mary; Wrin, Terri; Schooley, Robert T.; Lederman, Michael M.; Kuritzkes, Daniel R.

2014-01-01

Objectives To evaluate the impact of therapeutic HIV vaccination on the HIV reservoir, and assess the relationship of the viral reservoir with HIV-specific immune status and viral rebound kinetics. Design Retrospective analysis of ACTG A5197, a randomized, placebo-controlled trial of a therapeutic rAd5 HIV-1 gag vaccine. Methods Participants received vaccine/placebo at weeks 0, 4, and 26 prior to a 16-week analytic treatment interruption (ATI) at week 38. Cell-associated HIV-1 RNA and DNA (CA-RNA and CA-DNA) and HIV-1 residual viremia (RV) were quantified at weeks 0, 8, and 38. HIV-specific CD4+/CD8+ activity were assessed by an intracellular cytokine staining assay. Results At study entry, CA-RNA and CA-DNA levels were correlated inversely with the numbers of HIV-specific CD4+ interferon-γ-producing cells (CA-RNA: r = −0.23, P=0.03 and CA-DNA: r = −0.28, P<0.01, N=93). Therapeutic HIV vaccination induced HIV-specific CD4+ activity, but did not significantly affect levels of CA-RNA or CA-DNA. Vaccine recipients with undetectable RV at week 8 had higher frequencies of HIV-specific CD4+ and CD8+ interferon-γ-producing cells (undetectable versus detectable RV: 277 versus 161 CD4+ cells/106 lymphocytes, P=0.03 and 1326 versus 669 CD8+ cells/106 lymphocytes, P=0.04). Pre-ATI CA-RNA and CA-DNA were associated with post-ATI plasma HIV set point (CA-RNA: r = 0.51, P<0.01 and CA-DNA: r = 0.47, P<0.01). Conclusions Vaccine-induced T-cell responses were associated with a modest transient effect on RV, but more potent immune responses and/or combination treatment with latency-reversing agents are needed to reduce the HIV reservoir. HIV reservoir measures may act as biomarkers of post-ATI viral rebound kinetics. PMID:25254301

Is an HIV vaccine possible?

Directory of Open Access Journals (Sweden)

Nancy A. Wilson

Full Text Available The road to the discovery of a vaccine for HIV has been arduous and will continue to be difficult over the ensuing twenty years. Most vaccines are developed by inducing neutralizing antibodies against the target pathogen or by using attenuated strains of the particular pathogen to engender a variety of protective immune responses. Unfortunately, simple methods of generating anti-HIV antibodies have already failed in a phase III clinical trial. While attenuated SIV variants work well against homologous challenges in non-human primates, the potential for reversion to a more pathogenic virus and recombination with challenge viruses will preclude the use of attenuated HIV in the field. It has been exceedingly frustrating to vaccinate for HIV-specific neutralizing antibodies given the enormous diversity of the Envelope (Env glycoprotein and its well-developed glycan shield. However, there are several antibodies that will neutralize many different strains of HIV and inducing these types of antibodies in vaccinees remains the goal of a vigorous effort to develop a vaccine for HIV based on neutralizing antibodies. Given the difficulty in generating broadly reactive neutralizing antibodies, the HIV vaccine field has turned its attention to inducing T cell responses against the virus using a variety of vectors. Unfortunately, the results from Merck's phase IIb STEP trial proved to be disappointing. Vaccinees received Adenovirus type 5 (Ad5 expressing Gag, Pol, and Nef of HIV. This vaccine regimen failed to either prevent infection or reduce the level of HIV replication after challenge. These results mirrored those in non-human primate testing of Ad5 using rigorous SIV challenge models. This review will focus on recent developments in HIV vaccine development. We will deal largely with attempts to develop a T cell-based vaccine using the non-human primate SIV challenge model.

In “Step” with HIV Vaccines? A Content Analysis of Local Recruitment Campaigns for an International HIV Vaccine Study

Science.gov (United States)

Frew, Paula M.; Macias, Wendy; Chan, Kayshin; Harding, Ashley C.

2009-01-01

During the past two decades of the HIV/AIDS pandemic, several recruitment campaigns were designed to generate community involvement in preventive HIV vaccine clinical trials. These efforts utilized a blend of advertising and marketing strategies mixed with public relations and community education approaches to attract potential study participants to clinical trials (integrated marketing communications). Although more than 30,000 persons worldwide have participated in preventive HIV vaccine studies, no systematic analysis of recruitment campaigns exists. This content analysis study was conducted to examine several United States and Canadian recruitment campaigns for one of the largest-scale HIV vaccine trials to date (the “Step Study”). This study examined persuasive features consistent with the Elaboration Likelihood Model (ELM) including message content, personal relevance of HIV/AIDS and vaccine research, intended audiences, information sources, and other contextual features. The results indicated variation in messages and communication approaches with gay men more exclusively targeted in these regions. Racial/ethnic representations also differed by campaign. Most of the materials promote affective evaluation of the information through heuristic cueing. Implications for subsequent campaigns and research directions are discussed. PMID:19609373

HIV Vaccine for Prevention and Cure, A Mission Possible.

Science.gov (United States)

Lu, Da-Yong; Wu, Hong-Ying; Ding, Jian; Sastry, Nagendra; Lu, Ting-Ren

2016-01-01

HIV/AIDS was once a highly deadly infective disease that killed the global people of a million annually two decades ago. While we are enjoying the HIV therapeutic advances (mostly important from HAART invention), one obvious drawback is still unresolved-unable to clearance all HIV from infected human bodies. As a result, a series of different therapeutic attempts have been proposed based on present knowledge of different features of HIV-induced pathogenesis and human mortalities. Facing this shortcoming, innovative designs and update of HIV vaccines and other types of HIV therapeutic inventions can be a final solution for completely HIV clearance and infection managements in human beings. Owing to these scientific and medical significances, several experimental and clinical attempts have to be made. Among these attempts, part of them (updating HIV vaccine developments and clinical routines) are quite promising and noteworthy. In this article, we offer the general information of this attempt and discuss it separately, especially on the respects of HIV vaccine strategic innovations.

Comprehensive sieve analysis of breakthrough HIV-1 sequences in the RV144 vaccine efficacy trial.

Science.gov (United States)

Edlefsen, Paul T; Rolland, Morgane; Hertz, Tomer; Tovanabutra, Sodsai; Gartland, Andrew J; deCamp, Allan C; Magaret, Craig A; Ahmed, Hasan; Gottardo, Raphael; Juraska, Michal; McCoy, Connor; Larsen, Brendan B; Sanders-Buell, Eric; Carrico, Chris; Menis, Sergey; Kijak, Gustavo H; Bose, Meera; Arroyo, Miguel A; O'Connell, Robert J; Nitayaphan, Sorachai; Pitisuttithum, Punnee; Kaewkungwal, Jaranit; Rerks-Ngarm, Supachai; Robb, Merlin L; Kirys, Tatsiana; Georgiev, Ivelin S; Kwong, Peter D; Scheffler, Konrad; Pond, Sergei L Kosakovsky; Carlson, Jonathan M; Michael, Nelson L; Schief, William R; Mullins, James I; Kim, Jerome H; Gilbert, Peter B

2015-02-01

The RV144 clinical trial showed the partial efficacy of a vaccine regimen with an estimated vaccine efficacy (VE) of 31% for protecting low-risk Thai volunteers against acquisition of HIV-1. The impact of vaccine-induced immune responses can be investigated through sieve analysis of HIV-1 breakthrough infections (infected vaccine and placebo recipients). A V1/V2-targeted comparison of the genomes of HIV-1 breakthrough viruses identified two V2 amino acid sites that differed between the vaccine and placebo groups. Here we extended the V1/V2 analysis to the entire HIV-1 genome using an array of methods based on individual sites, k-mers and genes/proteins. We identified 56 amino acid sites or "signatures" and 119 k-mers that differed between the vaccine and placebo groups. Of those, 19 sites and 38 k-mers were located in the regions comprising the RV144 vaccine (Env-gp120, Gag, and Pro). The nine signature sites in Env-gp120 were significantly enriched for known antibody-associated sites (p = 0.0021). In particular, site 317 in the third variable loop (V3) overlapped with a hotspot of antibody recognition, and sites 369 and 424 were linked to CD4 binding site neutralization. The identified signature sites significantly covaried with other sites across the genome (mean = 32.1) more than did non-signature sites (mean = 0.9) (p analysis of the breakthrough infections in the RV144 trial, this work describes a set of statistical methods and tools applicable to analysis of breakthrough infection genomes in general vaccine efficacy trials for diverse pathogens.

Phase 1 safety and immunogenicity evaluation of ADMVA, a multigenic, modified vaccinia Ankara-HIV-1 B'/C candidate vaccine.

Directory of Open Access Journals (Sweden)

Sandhya Vasan

Full Text Available BACKGROUND: We conducted a Phase I dose-escalation trial of ADMVA, a Clade-B'/C-based HIV-1 candidate vaccine expressing env, gag, pol, nef, and tat in a modified vaccinia Ankara viral vector. Sequences were derived from a prevalent circulating HIV-1 recombinant form in Yunnan, China, an area of high HIV incidence. The objective was to evaluate the safety and immunogenicity of ADMVA in human volunteers. METHODOLOGY/PRINCIPAL FINDINGS: ADMVA or placebo was administered intramuscularly at months 0, 1 and 6 to 50 healthy adult volunteers not at high risk for HIV-1. In each dosage group [1x10(7 (low, 5x10(7 (mid, or 2.5x10(8 pfu (high] volunteers were randomized in a 3:1 ratio to receive ADMVA or placebo in a double-blinded design. Subjects were followed for local and systemic reactogenicity, adverse events including cardiac adverse events, and clinical laboratory parameters. Study follow up was 18 months. Humoral immunogenicity was evaluated by anti-gp120 binding ELISA, immunoflourescent staining, and HIV-1 neutralization. Cellular immunogenicity was assessed by a validated IFNgamma ELISpot assay and intracellular cytokine staining. Anti-vaccinia binding titers were measured by ELISA. ADMVA was generally well-tolerated, with no vaccine-related serious adverse events or cardiac adverse events. Local or systemic reactogenicity events were reported by 77% and 78% of volunteers, respectively. The majority of events were of mild intensity. The IFNgamma ELISpot response rate to any HIV antigen was 0/12 (0% in the placebo group, 3/12 (25% in the low dosage group, 6/12 (50% in the mid dosage group, and 8/13 (62% in the high dosage group. Responses were often multigenic and occasionally persisted up to one year post vaccination. Antibodies to gp120 were detected in 0/12 (0%, 8/13 (62%, 6/12 (50% and 10/13 (77% in the placebo, low, mid, and high dosage groups, respectively. Antibodies persisted up to 12 months after vaccination, with a trend toward agreement

Comprehensive sieve analysis of breakthrough HIV-1 sequences in the RV144 vaccine efficacy trial.

Directory of Open Access Journals (Sweden)

Paul T Edlefsen

2015-02-01

Full Text Available The RV144 clinical trial showed the partial efficacy of a vaccine regimen with an estimated vaccine efficacy (VE of 31% for protecting low-risk Thai volunteers against acquisition of HIV-1. The impact of vaccine-induced immune responses can be investigated through sieve analysis of HIV-1 breakthrough infections (infected vaccine and placebo recipients. A V1/V2-targeted comparison of the genomes of HIV-1 breakthrough viruses identified two V2 amino acid sites that differed between the vaccine and placebo groups. Here we extended the V1/V2 analysis to the entire HIV-1 genome using an array of methods based on individual sites, k-mers and genes/proteins. We identified 56 amino acid sites or "signatures" and 119 k-mers that differed between the vaccine and placebo groups. Of those, 19 sites and 38 k-mers were located in the regions comprising the RV144 vaccine (Env-gp120, Gag, and Pro. The nine signature sites in Env-gp120 were significantly enriched for known antibody-associated sites (p = 0.0021. In particular, site 317 in the third variable loop (V3 overlapped with a hotspot of antibody recognition, and sites 369 and 424 were linked to CD4 binding site neutralization. The identified signature sites significantly covaried with other sites across the genome (mean = 32.1 more than did non-signature sites (mean = 0.9 (p < 0.0001, suggesting functional and/or structural relevance of the signature sites. Since signature sites were not preferentially restricted to the vaccine immunogens and because most of the associations were insignificant following correction for multiple testing, we predict that few of the genetic differences are strongly linked to the RV144 vaccine-induced immune pressure. In addition to presenting results of the first complete-genome analysis of the breakthrough infections in the RV144 trial, this work describes a set of statistical methods and tools applicable to analysis of breakthrough infection genomes in general vaccine

Are Clade Specific HIV Vaccines a Necessity? An Analysis Based on Mathematical Models

Directory of Open Access Journals (Sweden)

Dobromir Dimitrov

2015-12-01

Full Text Available As HIV-1 envelope immune responses are critical to vaccine related protection, most candidate HIV vaccines entering efficacy trials are based upon a clade specific design. This need for clade specific vaccine prototypes markedly reduces the implementation of potentially effective HIV vaccines. We utilized a mathematical model to determine the effectiveness of immediate roll-out of a non-clade matched vaccine with reduced efficacy compared to constructing clade specific vaccines, which would take considerable time to manufacture and test in safety and efficacy trials. We simulated the HIV epidemic in San Francisco (SF and South Africa (SA and projected effectiveness of three vaccination strategies: i immediate intervention with a 20–40% vaccine efficacy (VE non-matched vaccine, ii delayed intervention by developing a 50% VE clade-specific vaccine, and iii immediate intervention with a non-matched vaccine replaced by a clade-specific vaccine when developed. Immediate vaccination with a non-clade matched vaccine, even with reduced efficacy, would prevent thousands of new infections in SF and millions in SA over 30 years. Vaccination with 50% VE delayed for five years needs six and 12 years in SA to break-even with immediate 20 and 30% VE vaccination, respectively, while not able to surpass the impact of immediate 40% VE vaccination over 30 years. Replacing a 30% VE with a 50% VE vaccine after 5 years reduces the HIV acquisition by 5% compared to delayed vaccination. The immediate use of an HIV vaccine with reduced VE in high risk communities appears desirable over a short time line but higher VE should be the pursued to achieve strong long-term impact. Our analysis illustrates the importance of developing surrogate markers (correlates of protection to allow bridging types of immunogenicity studies to support more rapid assessment of clade specific vaccines.

Feline immunodeficiency virus model for designing HIV/AIDS vaccines.

Science.gov (United States)

Yamamoto, Janet K; Sanou, Missa P; Abbott, Jeffrey R; Coleman, James K

2010-01-01

Feline immunodeficiency virus (FIV) discovered in 1986 is a lentivirus that causes AIDS in domestic cats. FIV is classified into five subtypes (A-E), and all subtypes and circulating intersubtype recombinants have been identified throughout the world. A commercial FIV vaccine, consisting of inactivated subtype-A and -D viruses (Fel-O-Vax FIV, Fort Dodge Animal Health), was released in the United States in 2002. The United States Department of Agriculture approved the commercial release of Fel-O-Vax FIV based on two efficacy trials using 105 laboratory cats and a major safety trial performed on 689 pet cats. The prototype and commercial FIV vaccines had broad prophylactic efficacy against global FIV subtypes and circulating intersubtype recombinants. The mechanisms of cross-subtype efficacy are attributed to FIV-specific T-cell immunity. Findings from these studies are being used to define the prophylactic epitopes needed for an HIV-1 vaccine for humans.

SieveSifter: a web-based tool for visualizing the sieve analyses of HIV-1 vaccine efficacy trials.

Science.gov (United States)

Fiore-Gartland, Andrew; Kullman, Nicholas; deCamp, Allan C; Clenaghan, Graham; Yang, Wayne; Magaret, Craig A; Edlefsen, Paul T; Gilbert, Peter B

2017-08-01

Analysis of HIV-1 virions from participants infected in a randomized controlled preventive HIV-1 vaccine efficacy trial can help elucidate mechanisms of partial protection. By comparing the genetic sequence of viruses from vaccine and placebo recipients to the sequence of the vaccine itself, a technique called 'sieve analysis', one can identify functional specificities of vaccine-induced immune responses. We have created an interactive web-based visualization and data access tool for exploring the results of sieve analyses performed on four major preventive HIV-1 vaccine efficacy trials: (i) the HIV Vaccine Trial Network (HVTN) 502/Step trial, (ii) the RV144/Thai trial, (iii) the HVTN 503/Phambili trial and (iv) the HVTN 505 trial. The tool acts simultaneously as a platform for rapid reinterpretation of sieve effects and as a portal for organizing and sharing the viral sequence data. Access to these valuable datasets also enables the development of novel methodology for future sieve analyses. Visualization: http://sieve.fredhutch.org/viz . Source code: https://github.com/nkullman/SIEVE . Data API: http://sieve.fredhutch.org/data . agartlan@fredhutch.org. © The Author(s) 2017. Published by Oxford University Press.

A therapeutic HIV vaccine using coxsackie-HIV recombinants: a possible new strategy.

Science.gov (United States)

Halim, S S; Collins, D N; Ramsingh, A I

2000-10-10

The ultimate goal in the treatment of HIV-infected persons is to prevent disease progression. A strategy to accomplish this goal is to use chemotherapy to reduce viral load followed by immunotherapy to stimulate HIV-specific immune responses that are observed in long-term asymptomatic individuals. An effective, live, recombinant virus, expressing HIV sequences, would be capable of inducing both CTL and CD4(+) helper T cell responses. To accomplish these goals, the viral vector must be immunogenic yet retain its avirulent phenotype in a T cell-deficient host. We have identified a coxsackievirus variant, CB4-P, that can induce protective immunity against a virulent variant. In addition, the CB4-P variant remains avirulent in mice lacking CD4(+) helper T cells, suggesting that CB4-P may be uniquely suited as a viral vector for a therapeutic HIV vaccine. Two strategies designed to elicit CTL and CD4(+) helper T cell responses were used to construct CB4-P/HIV recombinants. Recombinant viruses were viable, genetically stable, and retained the avirulent phenotype of the parental virus. In designing a viral vector for vaccine development, an issue that must be addressed is whether preexisting immunity to the vector would affect subsequent administration of the recombinant virus. Using a test recombinant, we showed that prior exposure to the parental CB4-P virus did not affect the ability of the recombinant to induce a CD4(+) T cell response against the foreign sequence. The results suggest that a "cocktail" of coxsackie/HIV recombinants may be useful as a therapeutic HIV vaccine.

The potential global market size and public health value of an HIV-1 vaccine in a complex global market.

Science.gov (United States)

Marzetta, Carol A; Lee, Stephen S; Wrobel, Sandra J; Singh, Kanwarjit J; Russell, Nina; Esparza, José

2010-07-05

An effective HIV vaccine will be essential for the control of the HIV pandemic. This study evaluated the potential global market size and value of a hypothetical HIV vaccine and considered clade diversity, disease burden, partial prevention of acquisition, impact of a reduction in viral load resulting in a decrease in transmission and delay to treatment, health care system differences regarding access, and HIV screening and vaccination, across all public and private markets. Vaccine product profiles varied from a vaccine that would have no effect on preventing infection to a vaccine that would effectively prevent infection and reduce viral load. High disease burden countries (HDBC; HIV prevalence > or = 1%) were assumed to routinely vaccinate pre-sexually active adolescents (10 years old), whereas low disease burden countries (LDBC; HIV prevalence rate market value of $210 million to $2.7 billion, depending on the vaccine product profile. If one-time catch-up campaigns were included (11-14 years old for HDBC and higher risk groups for LDBC), the additional cumulative approximately 70-237 million doses were needed over a 10-year period with a potential market value of approximately $695 million to $13.4 billion, depending on the vaccine product profile. Market size and value varied across market segments with the majority of the value in high income countries and the majority of the demand in low income countries. However, the value of the potential market in low income countries is still significant with up to $550 million annually for routine vaccination only and up to $1.7 billion for a one-time only catch-up campaign in 11-14 years old. In the most detail to date, this study evaluated market size and value of a potential multi-clade HIV vaccine, accounting for differences in disease burden, product profile and health care complexities. These findings provide donors and suppliers highly credible new data to consider in their continued efforts to develop an HIV-1

Plant-based anti-HIV-1 strategies: vaccine molecules and antiviral approaches.

Science.gov (United States)

Scotti, Nunzia; Buonaguro, Luigi; Tornesello, Maria Lina; Cardi, Teodoro; Buonaguro, Franco Maria

2010-08-01

The introduction of highly active antiretroviral therapy has drastically changed HIV infection from an acute, very deadly, to a chronic, long-lasting, mild disease. However, this requires continuous care management, which is difficult to implement worldwide, especially in developing countries. Sky-rocketing costs of HIV-positive subjects and the limited success of preventive recommendations mean that a vaccine is urgently needed, which could be the only effective strategy for the real control of the AIDS pandemic. To be effective, vaccination will need to be accessible, affordable and directed against multiple antigens. Plant-based vaccines, which are easy to produce and administer, and require no cold chain for their heat stability are, in principle, suited to such a strategy. More recently, it has been shown that even highly immunogenic, enveloped plant-based vaccines can be produced at a competitive and more efficient rate than conventional strategies. The high variability of HIV epitopes and the need to stimulate both humoral neutralizing antibodies and cellular immunity suggest the importance of using the plant system: it offers a wide range of possible strategies, from single-epitope to multicomponent vaccines, modulators of the immune response (adjuvants) and preventive molecules (microbicides), either alone or in association with plant-derived monoclonal antibodies, besides the potential use of the latter as therapeutic agents. Furthermore, plant-based anti-HIV strategies can be administered not only parenterally but also by the more convenient and safer oral route, which is a more suitable approach for possible mass vaccination.

Evaluation of yellow fever virus 17D strain as a new vector for HIV-1 vaccine development.

Science.gov (United States)

Franco, David; Li, Wenjing; Qing, Fang; Stoyanov, Cristina T; Moran, Thomas; Rice, Charles M; Ho, David D

2010-08-09

The failure to develop an effective vaccine against HIV-1 infection has led the research community to seek new ways of raising qualitatively different antibody and cellular immune responses. Towards this goal, we investigated the yellow fever 17D vaccine strain (YF17D), one of the most effective vaccines ever made, as a platform for HIV-1 vaccine development. A test antigen, HIV-1 p24 (clade B consensus), was inserted near the 5' end of YF17D, in frame and upstream of the polyprotein (YF-5'/p24), or between the envelope and the first non-structural protein (YF-E/p24/NS1). In vitro characterization of these recombinants indicated that the gene insert was more stable in the context of YF-E/p24/NS1. This was confirmed in immunogenicity studies in mice. CD8(+) IFN-gamma T-cell responses against p24 were elicited by the YF17D recombinants, as were specific CD4(+) T cells expressing IFN-gamma and IL-2. A balanced CD4(+) and CD8(+) T-cell response was notable, as was the polyfunctionality of the responding cells. Finally, the protective efficacy of the YF17D recombinants, particularly YF-E/p24/NS1, in mice challenged with a vaccinia expressing HIV-1 Gag was demonstrated. These results suggest that YF17D warrants serious consideration as a live-attenuated vector for HIV-1 vaccine development. Copyright 2010 Elsevier Ltd. All rights reserved.

The porcine circovirus type 1 capsid gene promoter improves antigen expression and immunogenicity in a HIV-1 plasmid vaccine

Directory of Open Access Journals (Sweden)

Burger Marieta

2011-02-01

Full Text Available Abstract Background One of the promising avenues for development of vaccines against Human immunodeficiency virus type 1 (HIV-1 and other human pathogens is the use of plasmid-based DNA vaccines. However, relatively large doses of plasmid must be injected for a relatively weak response. We investigated whether genome elements from Porcine circovirus type 1 (PCV-1, an apathogenic small ssDNA-containing virus, had useful expression-enhancing properties that could allow dose-sparing in a plasmid vaccine. Results The linearised PCV-1 genome inserted 5' of the CMV promoter in the well-characterised HIV-1 plasmid vaccine pTHgrttnC increased expression of the polyantigen up to 2-fold, and elicited 3-fold higher CTL responses in mice at 10-fold lower doses than unmodified pTHgrttnC. The PCV-1 capsid gene promoter (Pcap alone was equally effective. Enhancing activity was traced to a putative composite host transcription factor binding site and a "Conserved Late Element" transcription-enhancing sequence previously unidentified in circoviruses. Conclusions We identified a novel PCV-1 genome-derived enhancer sequence that significantly increased antigen expression from plasmids in in vitro assays, and improved immunogenicity in mice of the HIV-1 subtype C vaccine plasmid, pTHgrttnC. This should allow significant dose sparing of, or increased responses to, this and other plasmid-based vaccines. We also report investigations of the potential of other circovirus-derived sequences to be similarly used.

HIV vaccines: current challenges and future directions.

Science.gov (United States)

Avrett, Sam; Collins, Chris

2002-07-01

Volume seven of the Review will mark the tenth anniversary of the Canadian HIV/AIDS Legal Network with a series of articles that describe past developments and future directions in several areas of policy and law related to HIV/AIDS. The following article is the first of these, discussing current challenges and future directions in the development of and access to HIV vaccines. It argues that governments are under public health, ethical, and legal obligations to develop and provide access to HIV vaccines. It further explains what is required for governments to fulfill their obligations: additional commitment and resources for HIV vaccine development in the context of increased global research and development regarding diseases of the poor; increased support and advocacy for partnerships to develop HIV vaccines; enhanced regulatory capacity in every country to review, approve, and monitor HIV vaccines; and assurance of global supply of, procurement of, delivery of, and access to vaccines in the context of efforts to increase global access to public health measures and technologies.

Impact of aging and HIV infection on serologic response to seasonal influenza vaccination.

Science.gov (United States)

Pallikkuth, Suresh; De Armas, Lesley R; Pahwa, Rajendra; Rinaldi, Stefano; George, Varghese K; Sanchez, Celeste M; Pan, Li; Dickinson, Gordon; Rodriguez, Allan; Fischl, Margaret; Alcaide, Maria; Pahwa, Savita

2018-02-08

To determine influence of age and HIV infection on influenza vaccine responses. Evaluate serologic response to seasonal trivalent influenza vaccine (TIV) as the immunologic outcome in HIV-infected (HIV) and age-matched HIV negative (HIV) adults. During 2013-2016, 151 virologically controlled HIV individuals on antiretroviral therapy and 164 HIV volunteers grouped by age as young (<40 years), middle aged (40-59 years) and old (≥60 years) were administered TIV and investigated for serum antibody response to vaccine antigens. At prevaccination (T0) titers were in seroprotective range in more than 90% of participants. Antibody titers increased in all participants postvaccination but frequency of classified vaccine responders to individual or all three vaccine antigens at 3-4 weeks was higher in HIV than HIV adults with the greatest differences manifesting in the young age group. Of the three vaccine strains in TIV, antibody responses at T2 were weakest against H3N2 with those to H1N1 and B antigens dominating. Among the age groups, the titers for H1N1 and B were lowest in old age, with evidence of an age-associated interaction in HIV persons with antibody to B antigen. Greater frequencies of vaccine nonresponders are seen in HIV young compared with HIV adults and the observed age-associated interaction for B antigen in HIV persons are supportive of the concept of premature immune senescence in controlled HIV infection. High-potency influenza vaccination recommended for healthy aging could be considered for HIV adults of all ages.

Distinct susceptibility of HIV vaccine vector-induced CD4 T cells to HIV infection

Science.gov (United States)

Niu, Qingli; Hou, Wei; Churchyard, Gavin; Nitayaphan, Sorachai; Pitisuthithum, Punnee; Rerks-Ngarm, Supachai; Franchini, Genoveffa

2018-01-01

The concerns raised from adenovirus 5 (Ad5)-based HIV vaccine clinical trials, where excess HIV infections were observed in some vaccine recipients, have highlighted the importance of understanding host responses to vaccine vectors and the HIV susceptibility of vector-specific CD4 T cells in HIV vaccination. Our recent study reported that human Ad5-specific CD4 T cells induced by Ad5 vaccination (RV156A trial) are susceptible to HIV. Here we further investigated the HIV susceptibility of vector-specific CD4 T cells induced by ALVAC, a canarypox viral vector tested in the Thai trial RV144, as compared to Ad5 vector-specific CD4 T cells in the HVTN204 trial. We showed that while Ad5 vector-specific CD4 T cells were readily susceptible to HIV, ALVAC-specific CD4 T cells in RV144 PBMC were substantially less susceptible to both R5 and X4 HIV in vitro. The lower HIV susceptibility of ALVAC-specific CD4 T cells was associated with the reduced surface expression of HIV entry co-receptors CCR5 and CXCR4 on these cells. Phenotypic analyses identified that ALVAC-specific CD4 T cells displayed a strong Th1 phenotype, producing higher levels of IFN-γ and CCL4 (MIP-1β) but little IL-17. Of interest, ALVAC and Ad5 vectors induced distinct profiles of vector-specific CD8 vs. CD4 T-cell proliferative responses in PBMC, with ALVAC preferentially inducing CD8 T-cell proliferation, while Ad5 vector induced CD4 T-cell proliferation. Depletion of ALVAC-, but not Ad5-, induced CD8 T cells in PBMC led to a modest increase in HIV infection of vector-specific CD4 T cells, suggesting a role of ALVAC-specific CD8 T cells in protecting ALVAC-specific CD4 T cells from HIV. Taken together, our data provide strong evidence for distinct HIV susceptibility of CD4 T cells induced by different vaccine vectors and highlight the importance of better evaluating anti-vector responses in HIV vaccination. PMID:29474461

Safety and immunogenicity of adenovirus-vectored near-consensus HIV type 1 clade B gag vaccines in healthy adults.

Science.gov (United States)

Harro, Clayton D; Robertson, Michael N; Lally, Michelle A; O'Neill, Lori D; Edupuganti, Srilatha; Goepfert, Paul A; Mulligan, Mark J; Priddy, Frances H; Dubey, Sheri A; Kierstead, Lisa S; Sun, Xiao; Casimiro, Danilo R; DiNubile, Mark J; Shiver, John W; Leavitt, Randi Y; Mehrotra, Devan V

2009-01-01

Vaccines inducing pathogen-specific cell-mediated immunity are being developed using attenuated adenoviral (Ad) vectors. We report the results of two independent Phase I trials of similar replication-deficient Ad5 vaccines containing a near-consensus HIV-1 clade B gag transgene. Healthy HIV-uninfected adults were enrolled in two separate, multicenter, dose-escalating, blinded, placebo-controlled studies to assess the safety and immunogenicity of a three-dose homologous regimen of Ad5 and MRKAd5 HIV-1 gag vaccines given on day 1, week 4, and week 26. Adverse events were collected for 29 days following each intradeltoid injection. The primary immunogenicity endpoint was the proportion of subjects with a positive unfractionated Gag-specific IFN-gamma ELISPOT response measured 4 weeks after the last dose (week 30). Analyses were performed after combining data for each dose group from both protocols, stratifying by baseline Ad5 titers. Overall, 252 subjects were randomized to receive either vaccine or placebo, including 229 subjects (91%) who completed the study through week 30. Tolerability and immunogenicity did not appear to differ between the Ad5 and MRKAd5 vaccines. The frequency of injection-site reactions was dose dependent. Systemic adverse events were also dose dependent and more frequent in subjects with baseline Ad5 titers or =200, especially after the first dose. The percent of ELISPOT responders and the ELISPOT geometric means overall were significantly higher for all four vaccine doses studied compared to placebo, and were generally higher in vaccine recipients with baseline Ad5 titers or = 200. Ad5 titers increased after vaccination in a dose-dependent fashion. Both Ad5-vectored HIV-1 vaccines were generally well tolerated and induced cell-mediated immune responses against HIV Gag-peptides in the majority of healthy adults with baseline Ad5 titers vaccine-induced immunity to the Ad5 vector may dampen the CMI response to HIV Gag.

Immunoglobulin G1 Allotype Influences Antibody Subclass Distribution in Response to HIV gp140 Vaccination

Directory of Open Access Journals (Sweden)

Sven Kratochvil

2017-12-01

Full Text Available Antibody subclasses exhibit extensive polymorphisms (allotypes that could potentially impact the quality of HIV-vaccine induced B cell responses. Allotypes of immunoglobulin (Ig G1, the most abundant serum antibody, have been shown to display altered functional properties in regard to serum half-life, Fc-receptor binding and FcRn-mediated mucosal transcytosis. To investigate the potential link between allotypic IgG1-variants and vaccine-generated humoral responses in a cohort of 14 HIV vaccine recipients, we developed a novel protocol for rapid IgG1-allotyping. We combined PCR and ELISA assays in a dual approach to determine the IgG1 allotype identity (G1m3 and/or G1m1 of trial participants, using human plasma and RNA isolated from PBMC. The IgG1-allotype distribution of our participants mirrored previously reported results for caucasoid populations. We observed elevated levels of HIV gp140-specific IgG1 and decreased IgG2 levels associated with the G1m1-allele, in contrast to G1m3 carriers. These data suggest that vaccinees homozygous for G1m1 are predisposed to develop elevated Ag-specific IgG1:IgG2 ratios compared to G1m3-carriers. This elevated IgG1:IgG2 ratio was further associated with higher FcγR-dimer engagement, a surrogate for potential antibody-dependent cellular cytotoxicity (ADCC and antibody-dependent cellular phagocytosis (ADCP function. Although preliminary, these results suggest that IgG1 allotype may have a significant impact on IgG subclass distribution in response to vaccination and associated Fc-mediated effector functions. These results have important implications for ongoing HIV vaccine efficacy studies predicated on engagement of FcγR-mediated cellular functions including ADCC and ADCP, and warrant further investigation. Our novel allotyping protocol provides new tools to determine the potential impact of IgG1 allotypes on vaccine efficacy.

Sieve analysis of breakthrough HIV-1 sequences in HVTN 505 identifies vaccine pressure targeting the CD4 binding site of Env-gp120.

Science.gov (United States)

deCamp, Allan C; Rolland, Morgane; Edlefsen, Paul T; Sanders-Buell, Eric; Hall, Breana; Magaret, Craig A; Fiore-Gartland, Andrew J; Juraska, Michal; Carpp, Lindsay N; Karuna, Shelly T; Bose, Meera; LePore, Steven; Miller, Shana; O'Sullivan, Annemarie; Poltavee, Kultida; Bai, Hongjun; Dommaraju, Kalpana; Zhao, Hong; Wong, Kim; Chen, Lennie; Ahmed, Hasan; Goodman, Derrick; Tay, Matthew Z; Gottardo, Raphael; Koup, Richard A; Bailer, Robert; Mascola, John R; Graham, Barney S; Roederer, Mario; O'Connell, Robert J; Michael, Nelson L; Robb, Merlin L; Adams, Elizabeth; D'Souza, Patricia; Kublin, James; Corey, Lawrence; Geraghty, Daniel E; Frahm, Nicole; Tomaras, Georgia D; McElrath, M Juliana; Frenkel, Lisa; Styrchak, Sheila; Tovanabutra, Sodsai; Sobieszczyk, Magdalena E; Hammer, Scott M; Kim, Jerome H; Mullins, James I; Gilbert, Peter B

2017-01-01

Although the HVTN 505 DNA/recombinant adenovirus type 5 vector HIV-1 vaccine trial showed no overall efficacy, analysis of breakthrough HIV-1 sequences in participants can help determine whether vaccine-induced immune responses impacted viruses that caused infection. We analyzed 480 HIV-1 genomes sampled from 27 vaccine and 20 placebo recipients and found that intra-host HIV-1 diversity was significantly lower in vaccine recipients (P ≤ 0.04, Q-values ≤ 0.09) in Gag, Pol, Vif and envelope glycoprotein gp120 (Env-gp120). Furthermore, Env-gp120 sequences from vaccine recipients were significantly more distant from the subtype B vaccine insert than sequences from placebo recipients (P = 0.01, Q-value = 0.12). These vaccine effects were associated with signatures mapping to CD4 binding site and CD4-induced monoclonal antibody footprints. These results suggest either (i) no vaccine efficacy to block acquisition of any viral genotype but vaccine-accelerated Env evolution post-acquisition; or (ii) vaccine efficacy against HIV-1s with Env sequences closest to the vaccine insert combined with increased acquisition due to other factors, potentially including the vaccine vector.

Uptake of genital mucosal sampling in HVTN 097, a phase 1b HIV vaccine trial in South Africa.

Directory of Open Access Journals (Sweden)

Erica Maxine Lazarus

Full Text Available Because sexual transmission of HIV occurs across mucosal membranes, understanding the immune responses of the genital mucosa to vaccines may contribute knowledge to finding an effective candidate HIV vaccine. We describe the uptake of rectal secretion, cervical secretion and seminal mucosal secretion sampling amongst volunteers in a Phase 1b HIV vaccine trial. Age at screening, gender, study site and the designation of the person conducting the informed consent procedure were collected for volunteers who screened for the HVTN 097 study. A total of 211 volunteers (54% female were screened at three sites in South Africa: Soweto (n = 70, 33%, Cape Town (n = 68, 32% and Klerksdorp (n = 73, 35%. Overall uptake of optional mucosal sampling amongst trial volunteers was 71% (n = 149. Compared to Cape Town, volunteers from Soweto and Klerksdorp were less likely to consent to sampling (Soweto OR 0.08 CI: 0.03-0.25 p<0.001 and Klerksdorp OR 0.13 CI: 0.04-0.41 p = 0.001. In contrast, volunteers over 25 years of age were 2.39 times more likely to consent than younger volunteers (CI: 1.13-5.08, p = 0.02. Further studies are required to better understand the cultural, demographic and sociobehavioral factors which influence willingness to participate in mucosal sampling in HIV prevention studies.ClinicalTrials.gov: NCT02109354.

Vaccines for HIV | NCI Technology Transfer Center | TTC

Science.gov (United States)

The development of an effective HIV vaccine has been an ongoing area of research. The high variability in HIV-1 virus strains has represented a major challenge in successful development. Ideally, an effective candidate vaccine would provide protection against the majority of clades of HIV. Two major hurdles to overcome are immunodominance and sequence diversity. This vaccine utilizes a strategy for overcoming these two issues by identifying the conserved regions of the virus and exploiting them for use in a targeted therapy. NCI seeks licensees and/or research collaborators to commercialize this technology, which has been validated in macaque models.

Further progress on defining highly conserved immunogenic epitopes for a global HIV vaccine

DEFF Research Database (Denmark)

De Groot, Anne S; Levitz, Lauren; Ardito, Matthew T

2012-01-01

Two major obstacles confronting HIV vaccine design have been the extensive viral diversity of HIV-1 globally and viral evolution driven by escape from CD8(+) cytotoxic T-cell lymphocyte (CTL)-mediated immune pressure. Regions of the viral genome that are not able to escape immune response...

Safety of licensed vaccines in HIV-infected persons: a systematic review protocol

Science.gov (United States)

2014-01-01

Background Safety of vaccines remains a cornerstone of building public trust on the use of these cost-effective and life-saving public health interventions. In some settings, particularly Sub-Saharan Africa, there is a high prevalence of HIV infection and a high burden of vaccine-preventable diseases. There is evidence suggesting that the immunity induced by some commonly used vaccines is not durable in HIV-infected persons, and therefore, repeated vaccination may be considered to ensure optimal vaccine-induced immunity in this population. However, some vaccines, particularly the live vaccines, may be unsafe in HIV-infected persons. There is lack of evidence on the safety profile of commonly used vaccines among HIV-infected persons. We are therefore conducting a systematic review to assess the safety profile of routine vaccines administered to HIV-infected persons. Methods/Design We will select studies conducted in any setting where licensed and effective vaccines were administered to HIV-infected persons. We will search for eligible studies in PubMed, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, Africa-Wide, PDQ-Evidence and CINAHL as well as reference lists of relevant publications. We will screen search outputs, select studies and extract data in duplicate, resolving discrepancies by discussion and consensus. Discussion Globally, immunisation is a major public health strategy to mitigate morbidity and mortality caused by various infectious disease-causing agents. In general, there are efforts to increase vaccination coverage worldwide, and for these efforts to be successful, safety of the vaccines is paramount, even among people living with HIV, who in some situations may require repeated vaccination. Results from this systematic review will be discussed in the context of the safety of routine vaccines among HIV-infected persons. From the safety perspective, we will also discuss whether repeat vaccination strategies may be

The future of HIV vaccine research and the role of the Global HIV Vaccine Enterprise.

Science.gov (United States)

Voronin, Yegor; Manrique, Amapola; Bernstein, Alan

2010-09-01

This review covers the role of the Global HIV Vaccine Enterprise (the Enterprise), an alliance of independent organizations committed to development of a safe and effective HIV vaccine. It discusses the history, impact on the field, and future directions and initiatives of the alliance in the context of recent progress in HIV vaccine research and development. Significant progress has been made in the field since the release of the 2005 Scientific Strategic Plan (the Plan) of the Enterprise. Over the last year, the Enterprise embarked on an impact assessment of the 2005 Plan and the development of the 2010 Plan. Enterprise Working Groups identified key priorities in the field, several of which are discussed in this review, including changing the nature, purpose and process of clinical trials, increasing and facilitating data sharing, and optimizing existing and mobilizing new resources. This time is an important moment in HIV vaccine research. New clinical trial and laboratory results have created new opportunities to advance the search for an HIV vaccine and reinvigorated the field. The Enterprise will publish its 2010 Plan this year, providing a framework for setting new priorities and directions and encouraging new and existing partners to embark on a shared scientific agenda.

Understanding HIV infection for the design of a therapeutic vaccine. Part I: Epidemiology and pathogenesis of HIV infection.

Science.gov (United States)

de Goede, A L; Vulto, A G; Osterhaus, A D M E; Gruters, R A

2015-03-01

HIV infection leads to a gradual loss CD4+ T lymphocytes comprising immune competence and progression to AIDS. Effective treatment with combined antiretroviral drugs (cART) decreases viral load below detectable levels but is not able to eliminate the virus from the body. The success of cART is frustrated by the requirement of expensive life-long adherence, accumulating drug toxicities and chronic immune activation resulting in increased risk of several non-AIDS disorders, even when viral replication is suppressed. Therefore there is a strong need for therapeutic strategies as an alternative to cART. Immunotherapy, or therapeutic vaccination, aims to increase existing immune responses against HIV or induce de novo immune responses. These immune responses should provide a functional cure by controlling viral replication and preventing disease progression in the absence of cART. The key difficulty in the development of an HIV vaccine is our ignorance of the immune responses that control of viral replication, and thus how these responses can be elicited and how they can be monitored. Part one of this review provides an extensive overview of the (patho-) physiology of HIV infection. It describes the structure and replication cycle of HIV, the epidemiology and pathogenesis of HIV infection and the innate and adaptive immune responses against HIV. Part two of this review discusses therapeutic options for HIV. Prevention modalities and antiretroviral therapy are briefly touched upon, after which an extensive overview on vaccination strategies for HIV is provided, including the choice of immunogens and delivery strategies. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Reasons for ineligibility in phase 1 and 2A HIV vaccine clinical trials at Kenya AIDS vaccine initiative (KAVI, Kenya.

Directory of Open Access Journals (Sweden)

Gloria S Omosa-Manyonyi

2011-01-01

Full Text Available With the persistent challenges towards controlling the HIV epidemic, there is an ongoing need for research into HIV vaccines and drugs. Sub-Saharan African countries--worst affected by the HIV pandemic--have participated in the conduct of clinical trials for HIV vaccines. In Kenya, the Kenya AIDS Vaccine Initiative (KAVI at the University of Nairobi has conducted HIV vaccine clinical trials since 2001.Participants were recruited after an extensive informed consent process followed by screening to determine eligibility. Screening included an assessment of risk behavior, medical history and physical examination, and if clinically healthy, laboratory testing. In the absence of locally derived laboratory reference ranges, the ranges used in these trials were derived from populations in the West.Two hundred eighty-one participants were screened between 2003 and 2006 for two clinical trials. Of these, 167 (59.4% met the inclusion/exclusion criteria. Overall, laboratory abnormalities based on the non-indigenous laboratory references used were the most frequent reasons (61.4% for ineligibility. Medical abnormalities contributed 30.7% of the total reasons for ineligibility. Based on the laboratory reference intervals now developed from East and Southern Africa, those ineligible due to laboratory abnormalities would have been 46.3%. Of the eligible participants, 18.6% declined enrollment.Participant recruitment for HIV vaccine clinical trials is a rigorous and time-consuming exercise. Over 61% of the screening exclusions in clinically healthy people were due to laboratory abnormalities. It is essential that laboratory reference ranges generated from local populations for laboratory values be used in the conduct of clinical trials to avoid unnecessary exclusion of willing participants and to avoid over-reporting of adverse events for enrolled participants.Protocol IAVI VRC V001 [1]. ClinicalTrials.gov NCT00124007 Protocol IAVI 010 [2](registration with

Expression of HIV-1 antigens in plants as potential subunit vaccines

CSIR Research Space (South Africa)

Meyers, A

2008-06-23

Full Text Available Open AcceResearch article Expression of HIV-1 antigens in plants as potential subunit vaccines Ann Meyers1,2, Ereck Chakauya1,2,3, Enid Shephard1,4, Fiona L Tanzer1,2, James Maclean1,2, Alisson Lynch1,2, Anna-Lise Williamson1,5 and Edward P Rybicki...Figure 1 The HIV-1 Gag-derived proteins used in this study. Scale diagram showing (A) native Pr55Gag ORF organisation in the Page 2 of 15 (page number not for citation purposes) gag gene, (B) the p17/p24 fusion protein ORF, (C) p24 ORF. ORFs labelled p7...

Rational design of HIV vaccines and microbicides: report of the EUROPRISE annual conference 2011.

Science.gov (United States)

Ruffin, Nicolas; Borggren, Marie; Euler, Zelda; Fiorino, Fabio; Grupping, Katrijn; Hallengärd, David; Javed, Aneele; Mendonca, Kevin; Pollard, Charlotte; Reinhart, David; Saba, Elisa; Sheik-Khalil, Enas; Sköld, Annette; Ziglio, Serena; Scarlatti, Gabriella; Gotch, Frances; Wahren, Britta; Shattock, Robin J

2012-07-11

Europrise is a Network of Excellence supported by the European Commission within the 6th Framework programme from 2007 to 2012. The Network has involved over 50 institutions from 13 European countries together with 3 industrial partners and 6 African countries. The Network encompasses an integrated program of research, training, dissemination and advocacy within the field of HIV vaccines and microbicides. A central and timely theme of the Network is the development of the unique concept of co-usage of vaccines and microbicides. Training of PhD students has been a major task, and some of these post-graduate students have here summarized novel ideas emanating from presentations at the last annual Europrise meeting in Prague. The latest data and ideas concerning HIV vaccine and microbicide studies are included in this review; these studies are so recent that the majority have yet to be published. Data were presented and discussed concerning novel immunisation strategies; microbicides and PrEP (alone and in combination with vaccines); mucosal transmission of HIV/SIV; mucosal vaccination; novel adjuvants; neutralizing antibodies; innate immune responses; HIV/SIV pathogenesis and disease progression; new methods and reagents. These - necessarily overlapping topics - are comprehensively summarised by the Europrise students in the context of other recent exciting data.

Rational design of HIV vaccines and microbicides: report of the EUROPRISE annual conference 2011

Directory of Open Access Journals (Sweden)

Ruffin Nicolas

2012-07-01

Full Text Available Abstract Europrise is a Network of Excellence supported by the European Commission within the 6th Framework programme from 2007 to 2012. The Network has involved over 50 institutions from 13 European countries together with 3 industrial partners and 6 African countries. The Network encompasses an integrated program of research, training, dissemination and advocacy within the field of HIV vaccines and microbicides. A central and timely theme of the Network is the development of the unique concept of co-usage of vaccines and microbicides. Training of PhD students has been a major task, and some of these post-graduate students have here summarized novel ideas emanating from presentations at the last annual Europrise meeting in Prague. The latest data and ideas concerning HIV vaccine and microbicide studies are included in this review; these studies are so recent that the majority have yet to be published. Data were presented and discussed concerning novel immunisation strategies; microbicides and PrEP (alone and in combination with vaccines; mucosal transmission of HIV/SIV; mucosal vaccination; novel adjuvants; neutralizing antibodies; innate immune responses; HIV/SIV pathogenesis and disease progression; new methods and reagents. These – necessarily overlapping topics - are comprehensively summarised by the Europrise students in the context of other recent exciting data.

Induction of HIV neutralizing antibodies against the MPER of the HIV envelope protein by HA/gp41 chimeric protein-based DNA and VLP vaccines.

Directory of Open Access Journals (Sweden)

Ling Ye

Full Text Available Several conserved neutralizing epitopes have been identified in the HIV Env protein and among these, the MPER of gp41 has received great attention and is widely recognized as a promising target. However, little success has been achieved in eliciting MPER-specific HIV neutralizing antibodies by a number of different vaccine strategies. We investigated the ability of HA/gp41 chimeric protein-based vaccines, which were designed to enhance the exposure of the MPER in its native conformation, to induce MPER-specific HIV neutralizing antibodies. In characterization of the HA/gp41 chimeric protein, we found that by mutating an unpaired Cys residue (Cys-14 in its HA1 subunit to a Ser residue, the modified chimeric protein HA-C14S/gp41 showed increased reactivity to a conformation-sensitive monoclonal antibody against HA and formed more stable trimers in VLPs. On the other hand, HA-C14S/gp41 and HA/gp41 chimeric proteins expressed on the cell surfaces exhibited similar reactivity to monoclonal antibodies 2F5 and 4E10. Immunization of guinea pigs using the HA-C14S/gp41 DNA or VLP vaccines induced antibodies against the HIV gp41 as well as to a peptide corresponding to a segment of MPER at higher levels than immunization by standard HIV VLPs. Further, sera from vaccinated guinea pigs were found to exhibit HIV neutralizing activities. Moreover, sera from guinea pigs vaccinated by HA-C14S/gp41 DNA and VLP vaccines but not the standard HIV VLPs, were found to neutralize HIV pseudovirions containing a SIV-4E10 chimeric Env protein. The virus neutralization could be blocked by a MPER-specific peptide, thus demonstrating induction of MPER-specific HIV neutralizing antibodies by this novel vaccine strategy. These results show that induction of MPER-specific HIV neutralizing antibodies can be achieved through a rationally designed vaccine strategy.

Global panel of HIV-1 Env reference strains for standardized assessments of vaccine-elicited neutralizing antibodies.

Science.gov (United States)

deCamp, Allan; Hraber, Peter; Bailer, Robert T; Seaman, Michael S; Ochsenbauer, Christina; Kappes, John; Gottardo, Raphael; Edlefsen, Paul; Self, Steve; Tang, Haili; Greene, Kelli; Gao, Hongmei; Daniell, Xiaoju; Sarzotti-Kelsoe, Marcella; Gorny, Miroslaw K; Zolla-Pazner, Susan; LaBranche, Celia C; Mascola, John R; Korber, Bette T; Montefiori, David C

2014-03-01

Standardized assessments of HIV-1 vaccine-elicited neutralizing antibody responses are complicated by the genetic and antigenic variability of the viral envelope glycoproteins (Envs). To address these issues, suitable reference strains are needed that are representative of the global epidemic. Several panels have been recommended previously, but no clear answers have been available on how many and which strains are best suited for this purpose. We used a statistical model selection method to identify a global panel of reference Env clones from among 219 Env-pseudotyped viruses assayed in TZM-bl cells with sera from 205 HIV-1-infected individuals. The Envs and sera were sampled globally from diverse geographic locations and represented all major genetic subtypes and circulating recombinant forms of the virus. Assays with a panel size of only nine viruses adequately represented the spectrum of HIV-1 serum neutralizing activity seen with the larger panel of 219 viruses. An optimal panel of nine viruses was selected and augmented with three additional viruses for greater genetic and antigenic coverage. The spectrum of HIV-1 serum neutralizing activity seen with the final 12-virus panel closely approximated the activity seen with subtype-matched viruses. Moreover, the final panel was highly sensitive for detection of many of the known broadly neutralizing antibodies. For broader assay applications, all 12 Env clones were converted to infectious molecular clones using a proviral backbone carrying a Renilla luciferase reporter gene (Env.IMC.LucR viruses). This global panel should facilitate highly standardized assessments of vaccine-elicited neutralizing antibodies across multiple HIV-1 vaccine platforms in different parts of the world. An effective HIV-1 vaccine will need to overcome the extraordinary genetic variability of the virus, where most variation occurs in the viral envelope glycoproteins that are the sole targets for neutralizing antibodies. Efforts to elicit

Taking aim at a moving target: designing drugs to inhibit drug-resistant HIV-1 reverse transcriptases.

Science.gov (United States)

Sarafianos, Stefan G; Das, Kalyan; Hughes, Stephen H; Arnold, Eddy

2004-12-01

HIV undergoes rapid genetic variation; this variation is caused primarily by the enormous number of viruses produced daily in an infected individual. Because of this variation, HIV presents a moving target for drug and vaccine development. The variation within individuals has led to the generation of diverse HIV-1 subtypes, which further complicates the development of effective drugs and vaccines. In general, it is more difficult to hit a moving target than a stationary target. Two broad strategies for hitting a moving target (in this case, HIV replication) are to understand the movement and to aim at the portions that move the least. In the case of anti-HIV drug development, the first option can be addressed by understanding the mechanism(s) of drug resistance and developing drugs that effectively inhibit mutant viruses. The second can be addressed by designing drugs that interact with portions of the viral machinery that are evolutionarily conserved, such as enzyme active sites.

Safety and Immunogenicity of a Recombinant Adenovirus Serotype 35-Vectored HIV-1 Vaccine in Adenovirus Serotype 5 Seronegative and Seropositive Individuals.

Science.gov (United States)

Fuchs, Jonathan D; Bart, Pierre-Alexandre; Frahm, Nicole; Morgan, Cecilia; Gilbert, Peter B; Kochar, Nidhi; DeRosa, Stephen C; Tomaras, Georgia D; Wagner, Theresa M; Baden, Lindsey R; Koblin, Beryl A; Rouphael, Nadine G; Kalams, Spyros A; Keefer, Michael C; Goepfert, Paul A; Sobieszczyk, Magdalena E; Mayer, Kenneth H; Swann, Edith; Liao, Hua-Xin; Haynes, Barton F; Graham, Barney S; McElrath, M Juliana

2015-05-01

Recombinant adenovirus serotype 5 (rAd5)-vectored HIV-1 vaccines have not prevented HIV-1 infection or disease and pre-existing Ad5 neutralizing antibodies may limit the clinical utility of Ad5 vectors globally. Using a rare Ad serotype vector, such as Ad35, may circumvent these issues, but there are few data on the safety and immunogenicity of rAd35 directly compared to rAd5 following human vaccination. HVTN 077 randomized 192 healthy, HIV-uninfected participants into one of four HIV-1 vaccine/placebo groups: rAd35/rAd5, DNA/rAd5, and DNA/rAd35 in Ad5-seronegative persons; and DNA/rAd35 in Ad5-seropositive persons. All vaccines encoded the HIV-1 EnvA antigen. Antibody and T-cell responses were measured 4 weeks post boost immunization. All vaccines were generally well tolerated and similarly immunogenic. As compared to rAd5, rAd35 was equally potent in boosting HIV-1-specific humoral and cellular immunity and responses were not significantly attenuated in those with baseline Ad5 seropositivity. Like DNA, rAd35 efficiently primed rAd5 boosting. All vaccine regimens tested elicited cross-clade antibody responses, including Env V1/V2-specific IgG responses. Vaccine antigen delivery by rAd35 is well-tolerated and immunogenic as a prime to rAd5 immunization and as a boost to prior DNA immunization with the homologous insert. Further development of rAd35-vectored prime-boost vaccine regimens is warranted.

Time will tell: community acceptability of HIV vaccine research before and after the “Step Study” vaccine discontinuation

Directory of Open Access Journals (Sweden)

Paula M Frew

2010-09-01

Full Text Available Paula M Frew1,2,3,4, Mark J Mulligan1,2,3, Su-I Hou5, Kayshin Chan3, Carlos del Rio1,2,3,61Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA; 2Emory Center for AIDS Research, Atlanta, Georgia, USA; 3The Hope Clinic of the Emory Vaccine Center, Decatur, Georgia, USA; 4Department of Behavioral Sciences and Health Education, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA; 5Department of Health Promotion and Behavior, College of Public Health, University of Georgia, Athens, Georgia, USA; 6Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USAObjective: This study examines whether men-who-have-sex-with-men (MSM and transgender (TG persons’ attitudes, beliefs, and risk perceptions toward human immunodeficiency virus (HIV vaccine research have been altered as a result of the negative findings from a phase 2B HIV vaccine study.Design: We conducted a cross-sectional survey among MSM and TG persons (N = 176 recruited from community settings in Atlanta from 2007 to 2008. The first group was recruited during an active phase 2B HIV vaccine trial in which a candidate vaccine was being evaluated (the “Step Study”, and the second group was recruited after product futility was widely reported in the media.Methods: Descriptive statistics, t tests, and chi-square tests were conducted to ascertain differences between the groups, and ordinal logistic regressions examined the influences of the above-mentioned factors on a critical outcome, future HIV vaccine study participation. The ordinal regression outcomes evaluated the influences on disinclination, neutrality, and inclination to study participation.Results: Behavioral outcomes such as future recruitment, event attendance, study promotion, and community mobilization did not reveal any differences in participants’ intentions between the groups. However, we observed

Co-expression of HIV-1 virus-like particles and granulocyte-macrophage colony stimulating factor by GEO-D03 DNA vaccine

Science.gov (United States)

Hellerstein, Michael; Xu, Yongxian; Marino, Tracie; Lu, Shan; Yi, Hong; Wright, Elizabeth R.; Robinson, Harriet L.

2012-01-01

Here, we report on GEO-D03, a DNA vaccine that co-expresses non-infectious HIV-1 virus-like particles (VLPs) and the human cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF). The virus-like particles display the native gp160 form of the HIV-1 Envelope glycoprotein (Env) and are designed to elicit antibody against the natural form of Env on virus and virus-infected cells. The DNA-expressed HIV Gag, Pol and Env proteins also have the potential to elicit virus-specific CD4 and CD8 T cells. The purpose of the co-expressed GM-CSF is to target a cytokine that recruits, expands and differentiates macrophages and dendritic cells to the site of VLP expression. The GEO-D03 DNA vaccine is currently entered into human trials as a prime for a recombinant modified vaccinia Ankara (MVA) boost. In preclinical studies in macaques using an SIV prototype vaccine, this vaccination regimen elicited both anti-viral T cells and antibody, and provided 70% protection against acquisition during 12 weekly rectal exposures with a heterologous SIV. Higher avidity of the Env-specific Ab for the native form of the Env in the challenge virus correlated with lower likelihood of SIV infection. PMID:23111169

Randomized phase I trial HIV-CORE 003: Depletion of serum amyloid P component and immunogenicity of DNA vaccination against HIV-1.

Science.gov (United States)

Borthwick, Nicola J; Lane, Thirusha; Moyo, Nathifa; Crook, Alison; Shim, Jung Min; Baines, Ian; Wee, Edmund G; Hawkins, Philip N; Gillmore, Julian D; Hanke, Tomáš; Pepys, Mark B

2018-01-01

The failure of DNA vaccination in humans, in contrast to its efficacy in some species, is unexplained. Observational and interventional experimental evidence suggests that DNA immunogenicity may be prevented by binding of human serum amyloid P component (SAP). SAP is the single normal DNA binding protein in human plasma. The drug (R)-1-[6-[(R)-2-carboxypyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC, miridesap), developed for treatment of systemic amyloidosis and Alzheimer's disease, depletes circulating SAP by 95-99%. The proof-of-concept HIV-CORE 003 clinical trial tested whether SAP depletion by CPHPC would enhance the immune response in human volunteers to DNA vaccination delivering the HIVconsv immunogen derived from conserved sub-protein regions of HIV-1. Human volunteers received 3 intramuscular immunizations with an experimental DNA vaccine (DDD) expressing HIV-1-derived immunogen HIVconsv, with or without prior depletion of SAP by CPHPC. All subjects were subsequently boosted by simian (chimpanzee) adenovirus (C)- and poxvirus MVA (M)-vectored vaccines delivering the same immunogen. After administration of each vaccine modality, the peak total magnitudes, kinetics, functionality and memory subsets of the T-cell responses to HIVconsv were thoroughly characterized. No differences were observed between the CPHPC treated and control groups in any of the multiple quantitative and qualitative parameters of the T-cell responses to HIVconsv, except that after SAP depletion, there was a statistically significantly greater breadth of T-cell specificities, that is the number of recognized epitopes, following the DDDC vaccination. The protocol used here for SAP depletion by CPHPC prior to DNA vaccination produced only a very modest suggestion of enhanced immunogenicity. Further studies will be required to determine whether SAP depletion might have a practical value in DNA vaccination for other plasmid backbones and/or immunogens. Clinicaltrials

Is a HIV vaccine a viable option and at what price? An economic evaluation of adding HIV vaccination into existing prevention programs in Thailand

Directory of Open Access Journals (Sweden)

Peerapatanapokin Wiwat

2011-07-01

Full Text Available Abstract Background This study aims to determine the maximum price at which HIV vaccination is cost-effective in the Thai healthcare setting. It also aims to identify the relative importance of vaccine characteristics and risk behavior changes among vaccine recipients to determine how they affect this cost-effectiveness. Methods A semi-Markov model was developed to estimate the costs and health outcomes of HIV prevention programs combined with HIV vaccination in comparison to the existing HIV prevention programs without vaccination. The estimation was based on a lifetime horizon period (99 years and used the government perspective. The analysis focused on both the general population and specific high-risk population groups. The maximum price of cost-effective vaccination was defined by using threshold analysis; one-way and probabilistic sensitivity analyses were performed. The study employed an expected value of perfect information (EVPI analysis to determine the relative importance of parameters and to prioritize future studies. Results The most expensive HIV vaccination which is cost-effective when given to the general population was 12,000 Thai baht (US$1 = 34 Thai baht in 2009. This vaccination came with 70% vaccine efficacy and lifetime protection as long as risk behavior was unchanged post-vaccination. The vaccine would be considered cost-ineffective at any price if it demonstrated low efficacy (30% and if post-vaccination risk behavior increased by 10% or more, especially among the high-risk population groups. The incremental cost-effectiveness ratios were the most sensitive to change in post-vaccination risk behavior, followed by vaccine efficacy and duration of protection. The EVPI indicated the need to quantify vaccine efficacy, changed post-vaccination risk behavior, and the costs of vaccination programs. Conclusions The approach used in this study differentiated it from other economic evaluations and can be applied for the economic

Is a HIV vaccine a viable option and at what price? An economic evaluation of adding HIV vaccination into existing prevention programs in Thailand.

Science.gov (United States)

Leelahavarong, Pattara; Teerawattananon, Yot; Werayingyong, Pitsaphun; Akaleephan, Chutima; Premsri, Nakorn; Namwat, Chawetsan; Peerapatanapokin, Wiwat; Tangcharoensathien, Viroj

2011-07-05

This study aims to determine the maximum price at which HIV vaccination is cost-effective in the Thai healthcare setting. It also aims to identify the relative importance of vaccine characteristics and risk behavior changes among vaccine recipients to determine how they affect this cost-effectiveness. A semi-Markov model was developed to estimate the costs and health outcomes of HIV prevention programs combined with HIV vaccination in comparison to the existing HIV prevention programs without vaccination. The estimation was based on a lifetime horizon period (99 years) and used the government perspective. The analysis focused on both the general population and specific high-risk population groups. The maximum price of cost-effective vaccination was defined by using threshold analysis; one-way and probabilistic sensitivity analyses were performed. The study employed an expected value of perfect information (EVPI) analysis to determine the relative importance of parameters and to prioritize future studies. The most expensive HIV vaccination which is cost-effective when given to the general population was 12,000 Thai baht (US$1 = 34 Thai baht in 2009). This vaccination came with 70% vaccine efficacy and lifetime protection as long as risk behavior was unchanged post-vaccination. The vaccine would be considered cost-ineffective at any price if it demonstrated low efficacy (30%) and if post-vaccination risk behavior increased by 10% or more, especially among the high-risk population groups. The incremental cost-effectiveness ratios were the most sensitive to change in post-vaccination risk behavior, followed by vaccine efficacy and duration of protection. The EVPI indicated the need to quantify vaccine efficacy, changed post-vaccination risk behavior, and the costs of vaccination programs. The approach used in this study differentiated it from other economic evaluations and can be applied for the economic evaluation of other health interventions not available in

Discovery of novel targets for multi-epitope vaccines: Screening of HIV-1 genomes using association rule mining

Directory of Open Access Journals (Sweden)

Piontkivska Helen

2009-07-01

Full Text Available Abstract Background Studies have shown that in the genome of human immunodeficiency virus (HIV-1 regions responsible for interactions with the host's immune system, namely, cytotoxic T-lymphocyte (CTL epitopes tend to cluster together in relatively conserved regions. On the other hand, "epitope-less" regions or regions with relatively low density of epitopes tend to be more variable. However, very little is known about relationships among epitopes from different genes, in other words, whether particular epitopes from different genes would occur together in the same viral genome. To identify CTL epitopes in different genes that co-occur in HIV genomes, association rule mining was used. Results Using a set of 189 best-defined HIV-1 CTL/CD8+ epitopes from 9 different protein-coding genes, as described by Frahm, Linde & Brander (2007, we examined the complete genomic sequences of 62 reference HIV sequences (including 13 subtypes and sub-subtypes with approximately 4 representative sequences for each subtype or sub-subtype, and 18 circulating recombinant forms. The results showed that despite inclusion of recombinant sequences that would be expected to break-up associations of epitopes in different genes when two different genomes are recombined, there exist particular combinations of epitopes (epitope associations that occur repeatedly across the world-wide population of HIV-1. For example, Pol epitope LFLDGIDKA is found to be significantly associated with epitopes GHQAAMQML and FLKEKGGL from Gag and Nef, respectively, and this association rule is observed even among circulating recombinant forms. Conclusion We have identified CTL epitope combinations co-occurring in HIV-1 genomes including different subtypes and recombinant forms. Such co-occurrence has important implications for design of complex vaccines (multi-epitope vaccines and/or drugs that would target multiple HIV-1 regions at once and, thus, may be expected to overcome challenges

Safety and immunogenicity of an HIV-1 gag DNA vaccine with or without IL-12 and/or IL-15 plasmid cytokine adjuvant in healthy, HIV-1 uninfected adults.

Directory of Open Access Journals (Sweden)

Spyros A Kalams

Full Text Available DNA vaccines are a promising approach to vaccination since they circumvent the problem of vector-induced immunity. DNA plasmid cytokine adjuvants have been shown to augment immune responses in small animals and in macaques.We performed two first in human HIV vaccine trials in the US, Brazil and Thailand of an RNA-optimized truncated HIV-1 gag gene (p37 DNA derived from strain HXB2 administered either alone or in combination with dose-escalation of IL-12 or IL-15 plasmid cytokine adjuvants. Vaccinations with both the HIV immunogen and cytokine adjuvant were generally well-tolerated and no significant vaccine-related adverse events were identified. A small number of subjects developed asymptomatic low titer antibodies to IL-12 or IL-15. Cellular immunogenicity following 3 and 4 vaccinations was poor, with response rates to gag of 4.9%/8.7% among vaccinees receiving gag DNA alone, 0%/11.5% among those receiving gag DNA+IL-15, and no responders among those receiving DNA+high dose (1500 ug IL-12 DNA. However, after three doses, 44.4% (4/9 of vaccinees receiving gag DNA and intermediate dose (500 ug of IL-12 DNA demonstrated a detectable cellular immune response.This combination of HIV gag DNA with plasmid cytokine adjuvants was well tolerated. There were minimal responses to HIV gag DNA alone, and no apparent augmentation with either IL-12 or IL-15 plasmid cytokine adjuvants. Despite the promise of DNA vaccines, newer formulations or methods of delivery will be required to increase their immunogenicity.Clinicaltrials.gov NCT00115960 NCT00111605.

Yellow fever vaccine for patients with HIV infection.

Science.gov (United States)

Barte, Hilary; Horvath, Tara H; Rutherford, George W

2014-01-23

Yellow fever (YF) is an acute viral haemorrhagic disease prevalent in tropical Africa and Latin America. The World Health Organization (WHO) estimates that there are 200,000 cases of YF and 30,000 deaths worldwide annually. Treatment for YF is supportive, but a live attenuated virus vaccine is effective for preventing infection. WHO recommends immunisation for all individuals > 9 months living in countries or areas at risk. However, the United States Advisory Committee on Immunization Practices (ACIP) advises that YF vaccine is contraindicated in individuals with HIV. Given the large populations of HIV-infected individuals living in tropical areas where YF is endemic, YF vaccine may be an important intervention for preventing YF in immunocompromised populations. To assess the risk and benefits of YF immunisation for people infected with HIV. We used standard Cochrane methods to search electronic databases and conference proceedings with relevant search terms without limits to language. Randomised controlled trials and cohort studies of individuals with HIV infection who received YF vaccine (17DD or 17D-204). Two authors screened abstracts of references identified by electronic or bibliographic searches according to inclusion and exclusion criteria as detailed in the protocol. We identified 199 references and examined 19 in detail for study eligibility. Data were abstracted independently using a standardised abstraction form. Three cohort studies were included in the review. They examined 484 patients with HIV infection who received YF immunisation. Patients with HIV infection developed significantly lower concentrations of neutralising antibodies in the first year post immunisation compared to uninfected patients, though decay patterns were similar for recipients regardless of HIV infection. No study patient with HIV infection suffered serious adverse events as a result of YF vaccination. YF vaccination can produce protective levels of neutralising antibodies in

Long-term follow-up of HIV-1-infected adults who received the F4/AS01B HIV-1 vaccine candidate in two randomised controlled trials.

Science.gov (United States)

Harrer, Thomas; Dinges, Warren; Roman, François

2018-05-03

This Phase I/II, open, long-term follow-up study was conducted in antiretroviral therapy (ART)-naïve (N = 212) and ART-treated (N = 19) human immunodeficiency virus 1 (HIV-1)-infected adults, who received an HIV-1 investigational vaccine (F4/AS01 B ) or placebo in two previous studies (NCT00814762 and NCT01218113). After a minimum of two years and a maximum of four years of follow-up post-vaccination per patient, no significant differences were observed between F4/AS01 B and placebo groups in terms of viral load, CD4 + T-cell count and incidence of specific clinical events. Vaccine-induced polyfunctional CD4 + T-cells persisted up to study end and no relevant vaccine-related safety events were reported in F4/AS01 B groups. This study has been registered at ClinicalTrials.gov (NCT01092611). Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Acceptance and tolerability of an adjuvanted nH1N1 vaccine in HIV-infected patients in the cologne-bonn cohort

Directory of Open Access Journals (Sweden)

Steffens B

2011-07-01

Full Text Available Abstract Objective To evaluate the acceptance and tolerability of the nH1N1 2009 vaccine in HIV-positive individuals. Method 758 patients were included in this prospective study. Different study populations were formed: The Tolerability Study Group consists of HIV-infected patients who visited three outpatient clinics (Cologne, Bonn, Freiburg during a predefined time period. Patients were offered nH1N1 vaccination. Those accepting were administered a standard dose AS03 adjuvant nH1N1 vaccine. Questionnaires to report side effects occurring within 7 days after immunization were handed out. In a substudy conducted during the same time period, acceptance towards immunization was recorded. This Acceptance Study Group consists of all HIV-infected patients visiting the Cologne clinic. They were offered vaccination. In case of refusal, motivation was recorded. Results In the Tolerability Study Group, a total of 475 patient diaries returned in the three study centres could be evaluated, 119 of those (25% reported no side effects. Distribution of symptoms was as follows: Pain 285/475 patients (60%, swelling 96 (20%, redness 54 (11%, fever 48/475 (10%, muscle/joint ache 173 (36%, headache 127 (27%, and fatigue 210 (44%. Association of side effects with clinical data was calculated for patients in Cologne and Bonn. Incidence of side effects was significantly associated with CDC stages A, B compared to C, and with a detectable viral load (> 50 copies/mL. No correlation was noted for CD4 cell count, age, gender or ethnicity. In the Acceptance Study Group, 538 HIV-infected patients were offered vaccination, 402 (75% accepted, while 136 (25% rejected. Main reasons for rejection were: Negative media coverage (35%, indecisiveness with preference to wait until a later date (23%, influenza not seen as personal threat (19% and scepticism towards immunization in general (10%. Conclusion A total of 622 HIV-infected patients were vaccinated against nH1N1-influenza in

A brief history of HIV vaccine research: stepping back to the drawing board?

Science.gov (United States)

Miedema, Frank

2008-09-12

In September 2007, it was announced that the most promising HIV vaccine trial had to be stopped because it had failed to show the protection that was hoped for. Here, the history of HIV vaccine development from the discovery of HIV-1 in 1983 until 2008, the underlying ideas on protective immunity to HIV and potential avenues for vaccine research are discussed.

Randomized Phase I: Safety, Immunogenicity and Mucosal Antiviral Activity in Young Healthy Women Vaccinated with HIV-1 Gp41 P1 Peptide on Virosomes.

Directory of Open Access Journals (Sweden)

Geert Leroux-Roels

Full Text Available Mucosal antibodies harboring various antiviral activities may best protect mucosal surfaces against early HIV-1 entry at mucosal sites and they should be ideally induced by prophylactic HIV-1 vaccines for optimal prevention of sexually transmitted HIV-1. A phase I, double-blind, randomized, placebo-controlled trial was conducted in twenty-four healthy HIV-uninfected young women. The study objectives were to assess the safety, tolerability and immunogenicity of virosomes harboring surface HIV-1 gp41-derived P1 lipidated peptides (MYM-V101. Participants received placebo or MYM-V101 vaccine at 10 μg/dose or 50 μg/dose intramuscularly at week 0 and 8, and intranasally at week 16 and 24. MYM-V101 was safe and well-tolerated at both doses administered by the intramuscular and intranasal routes, with the majority of subjects remaining free of local and general symptoms. P1-specific serum IgGs and IgAs were induced in all high dose recipients after the first injection. After the last vaccination, vaginal and rectal P1-specific IgGs could be detected in all high dose recipients. Approximately 63% and 43% of the low and high dose recipients were respectively tested positive for vaginal P1-IgAs, while 29% of the subjects from the high dose group tested positive for rectal IgAs. Serum samples had total specific IgG and IgA antibody concentrations ≥ 0.4 μg/mL, while mucosal samples were usually below 0.01 μg/mL. Vaginal secretions from MYM-V101 vaccinated subjects were inhibiting HIV-1 transcytosis but had no detectable neutralizing activity. P1-specific Th1 responses could not be detected on PBMC. This study demonstrates the excellent safety and tolerability of MYM-V101, eliciting systemic and mucosal antibodies in the majority of subjects. Vaccine-induced mucosal anti-gp41 antibodies toward conserved gp41 motifs were harboring HIV-1 transcytosis inhibition activity and may contribute to reduce sexually-transmitted HIV-1.ClinicalTrials.gov NCT01084343.

Basis and Statistical Design of the Passive HIV-1 Antibody Mediated Prevention (AMP) Test-of-Concept Efficacy Trials.

Science.gov (United States)

Gilbert, Peter B; Juraska, Michal; deCamp, Allan C; Karuna, Shelly; Edupuganti, Srilatha; Mgodi, Nyaradzo; Donnell, Deborah J; Bentley, Carter; Sista, Nirupama; Andrew, Philip; Isaacs, Abby; Huang, Yunda; Zhang, Lily; Capparelli, Edmund; Kochar, Nidhi; Wang, Jing; Eshleman, Susan H; Mayer, Kenneth H; Magaret, Craig A; Hural, John; Kublin, James G; Gray, Glenda; Montefiori, David C; Gomez, Margarita M; Burns, David N; McElrath, Julie; Ledgerwood, Julie; Graham, Barney S; Mascola, John R; Cohen, Myron; Corey, Lawrence

2017-01-01

Anti-HIV-1 broadly neutralizing antibodies (bnAbs) have been developed as potential agents for prevention of HIV-1 infection. The HIV Vaccine Trials Network and the HIV Prevention Trials Network are conducting the Antibody Mediated Prevention (AMP) trials to assess whether, and how, intravenous infusion of the anti-CD4 binding site bnAb, VRC01, prevents HIV-1 infection. These are the first test-of-concept studies to assess HIV-1 bnAb prevention efficacy in humans. The AMP trials are two parallel phase 2b HIV-1 prevention efficacy trials conducted in two cohorts: 2700 HIV-uninfected men and transgender persons who have sex with men in the United States, Peru, Brazil, and Switzerland; and 1500 HIV-uninfected sexually active women in seven countries in sub-Saharan Africa. Participants are randomized 1:1:1 to receive an intravenous infusion of 10 mg/kg VRC01, 30 mg/kg VRC01, or a control preparation every 8 weeks for a total of 10 infusions. Each trial is designed (1) to assess overall prevention efficacy (PE) pooled over the two VRC01 dose groups vs. control and (2) to assess VRC01 dose and laboratory markers as correlates of protection (CoPs) against overall and genotype- and phenotype-specific infection. Each AMP trial is designed to have 90% power to detect PE > 0% if PE is ≥ 60%. The AMP trials are also designed to identify VRC01 properties (i.e., concentration and effector functions) that correlate with protection and to provide insight into mechanistic CoPs. CoPs are assessed using data from breakthrough HIV-1 infections, including genetic sequences and sensitivities to VRC01-mediated neutralization and Fc effector functions. The AMP trials test whether VRC01 can prevent HIV-1 infection in two study populations. If affirmative, they will provide information for estimating the optimal dosage of VRC01 (or subsequent derivatives) and identify threshold levels of neutralization and Fc effector functions associated with high-level protection, setting a benchmark

Development of an anti-HIV vaccine eliciting broadly neutralizing antibodies.

Science.gov (United States)

Ahmed, Yousuf; Tian, Meijuan; Gao, Yong

2017-09-12

The extreme HIV diversity posts a great challenge on development of an effective anti-HIV vaccine. To solve this problem, it is crucial to discover an appropriate immunogens and strategies that are able to prevent the transmission of the diverse viruses that are circulating in the world. Even though there have been a number of broadly neutralizing anti-HIV antibodies (bNAbs) been discovered in recent years, induction of such antibodies to date has only been observed in HIV-1 infection. Here, in this mini review, we review the progress in development of HIV vaccine in eliciting broad immune response, especially production of bNAbs, discuss possible strategies, such as polyvalent sequential vaccination, that facilitates B cell maturation leading to bNAb response.

Virus-like-vaccines against HIV

DEFF Research Database (Denmark)

Andersson, Anne Marie C.; Schwerdtfeger, Melanie; Holst, Peter J.

2018-01-01

Protection against chronic infections has necessitated the development of ever-more potent vaccination tools. HIV seems to be the most challenging foe, with a remarkable, poorly immunogenic and fragile surface glycoprotein and the ability to overpower the cell immune system. Virus-like-particle (......Protection against chronic infections has necessitated the development of ever-more potent vaccination tools. HIV seems to be the most challenging foe, with a remarkable, poorly immunogenic and fragile surface glycoprotein and the ability to overpower the cell immune system. Virus...... of HIV. Such vaccines are immunologically perceived as viruses, as they infect cells and produce VLPs in situ, but they only resemble viruses, as the replication defective vectors and VLPs cannot propagate an infection. The inherent safety of such a platform, despite robust particle production...

Heterologous Prime-Boost HIV-1 Vaccination Regimens in Pre-Clinical and Clinical Trials

Directory of Open Access Journals (Sweden)

Julia L. Hurwitz

2010-02-01

Full Text Available Currently, there are more than 30 million people infected with HIV-1 and thousands more are infected each day. Vaccination is the single most effective mechanism for prevention of viral disease, and after more than 25 years of research, one vaccine has shown somewhat encouraging results in an advanced clinical efficacy trial. A modified intent-to-treat analysis of trial results showed that infection was approximately 30% lower in the vaccine group compared to the placebo group. The vaccine was administered using a heterologous prime-boost regimen in which both target antigens and delivery vehicles were changed during the course of inoculations. Here we examine the complexity of heterologous prime-boost immunizations. We show that the use of different delivery vehicles in prime and boost inoculations can help to avert the inhibitory effects caused by vector-specific immune responses. We also show that the introduction of new antigens into boost inoculations can be advantageous, demonstrating that the effect of ‘original antigenic sin’ is not absolute. Pre-clinical and clinical studies are reviewed, including our own work with a three-vector vaccination regimen using recombinant DNA, virus (Sendai virus or vaccinia virus and protein. Promising preliminary results suggest that the heterologous prime-boost strategy may possibly provide a foundation for the future prevention of HIV-1 infections in humans.

Newborn Mice Vaccination with BCG.HIVA222 + MVA.HIVA Enhances HIV-1-Specific Immune Responses: Influence of Age and Immunization Routes

Directory of Open Access Journals (Sweden)

Narcís Saubi

2011-01-01

Full Text Available We have evaluated the influence of age and immunization routes for induction of HIV-1- and M. tuberculosis-specific immune responses after neonatal (7 days old and adult (7 weeks old BALB/c mice immunization with BCG.HIVA222 prime and MVA.HIVA boost. The specific HIV-1 cellular immune responses were analyzed in spleen cells. The body weight of the newborn mice was weekly recorded. The frequencies of HIV-specific CD8+ T cells producing IFN-γ were higher in adult mice vaccinated intradermally and lower in adult and newborn mice vaccinated subcutaneously. In all cases the IFN-γ production was significantly higher when mice were primed with BCG.HIVA222 compared with BCGwt. When the HIV-specific CTL activity was assessed, the frequencies of specific killing were higher in newborn mice than in adults. The prime-boost vaccination regimen which includes BCG.HIVA222 and MVA.HIVA was safe when inoculated to newborn mice. The administration of BCG.HIVA222 to newborn mice is safe and immunogenic and increased the HIV-specific responses induced by MVA.HIVA vaccine. It might be a good model for infant HIV and Tuberculosis bivalent vaccine.

Newborn Mice Vaccination with BCG.HIVA222 + MVA.HIVA Enhances HIV-1-Specific Immune Responses: Influence of Age and Immunization Routes

Science.gov (United States)

Saubi, Narcís; Im, Eung-Jun; Fernández-Lloris, Raquel; Gil, Olga; Cardona, Pere-Joan; Gatell, Josep Maria; Hanke, Tomáš; Joseph, Joan

2011-01-01

We have evaluated the influence of age and immunization routes for induction of HIV-1- and M. tuberculosis-specific immune responses after neonatal (7 days old) and adult (7 weeks old) BALB/c mice immunization with BCG.HIVA222 prime and MVA.HIVA boost. The specific HIV-1 cellular immune responses were analyzed in spleen cells. The body weight of the newborn mice was weekly recorded. The frequencies of HIV-specific CD8+ T cells producing IFN-γ were higher in adult mice vaccinated intradermally and lower in adult and newborn mice vaccinated subcutaneously. In all cases the IFN-γ production was significantly higher when mice were primed with BCG.HIVA222 compared with BCGwt. When the HIV-specific CTL activity was assessed, the frequencies of specific killing were higher in newborn mice than in adults. The prime-boost vaccination regimen which includes BCG.HIVA222 and MVA.HIVA was safe when inoculated to newborn mice. The administration of BCG.HIVA222 to newborn mice is safe and immunogenic and increased the HIV-specific responses induced by MVA.HIVA vaccine. It might be a good model for infant HIV and Tuberculosis bivalent vaccine. PMID:21603216

Recombinant and epitope-based vaccines on the road to the market and implications for vaccine design and production.

Science.gov (United States)

Oyarzún, Patricio; Kobe, Bostjan

2016-03-03

Novel vaccination approaches based on rational design of B- and T-cell epitopes - epitope-based vaccines - are making progress in the clinical trial pipeline. The epitope-focused recombinant protein-based malaria vaccine (termed RTS,S) is a next-generation approach that successfully reached phase-III trials, and will potentially become the first commercial vaccine against a human parasitic disease. Progress made on methods such as recombinant DNA technology, advanced cell-culture techniques, immunoinformatics and rational design of immunogens are driving the development of these novel concepts. Synthetic recombinant proteins comprising both B- and T-cell epitopes can be efficiently produced through modern biotechnology and bioprocessing methods, and can enable the induction of large repertoires of immune specificities. In particular, the inclusion of appropriate CD4+ T-cell epitopes is increasingly considered a key vaccine component to elicit robust immune responses, as suggested by results coming from HIV-1 clinical trials. In silico strategies for vaccine design are under active development to address genetic variation in pathogens and several broadly protective "universal" influenza and HIV-1 vaccines are currently at different stages of clinical trials. Other methods focus on improving population coverage in target populations by rationally considering specificity and prevalence of the HLA proteins, though a proof-of-concept in humans has not been demonstrated yet. Overall, we expect immunoinformatics and bioprocessing methods to become a central part of the next-generation epitope-based vaccine development and production process.

Response to 2009 pandemic and seasonal influenza vaccines co-administered to HIV-infected and HIV-uninfected former drug users living in a rehabilitation community in Italy.

Science.gov (United States)

Pariani, Elena; Boschini, Antonio; Amendola, Antonella; Poletti, Raffaella; Anselmi, Giovanni; Begnini, Marco; Ranghiero, Alberto; Cecconi, Gianluca; Zanetti, Alessandro R

2011-11-15

2009 A(H1N1) pandemic influenza vaccination was recommended as a priority to essential workers and high-risk individuals, including HIV-infected patients and people living in communities. HIV-infected and HIV-uninfected former drug-users (18-60 years old) living in a rehabilitation community (San Patrignano, Italy) received one dose of a MF59-adjuvanted 2009 pandemic influenza vaccine and one dose of a 2009-2010 seasonal trivalent inactivated influenza vaccine (containing A/Brisbane/59/2007(H1N1), A/Brisbane/10/2007(H3N2), B/Brisbane/60/2008) simultaneously. Antibodies against each vaccine antigen were determined at the time of vaccination and one and six months post-vaccination by hemagglutination-inhibition test. 49 HIV-infected and 60 HIV-uninfected subjects completed the study. Most (98%) HIV-infected participants were on antiretroviral treatment, the median CD4+ cell count was 350 (IQR 300)cells/μl and viremia was suppressed in 91.8% of cases. One month post-vaccination, no significant changes in immune-virological parameters were observed. One month post-vaccination, the immune responses to both pandemic and seasonal vaccine met the EMA-CPMP criteria for immunogenicity of influenza vaccines in both HIV-infected and HIV-uninfected subjects. No difference in vaccine responses was observed between the two groups. Six months after vaccination, the percentages of vaccinees with antibody titres ≥1:40 and antibody geometric mean titres significantly decreased in both groups. However, they were significantly lower in HIV-infected than in HIV-uninfected vaccinees. In subjects who had been primed to seasonal influenza the year before (through either vaccination or natural infection), levels of antibodies against 2009 A(H1N1) were higher than those measured in unprimed subjects, both one month and six months post-vaccination. The co-administration of a single dose of 2009 pandemic MF59-adjuvanted influenza vaccine with a seasonal vaccine provided a protective immune

College Student Invulnerability Beliefs and HIV Vaccine Acceptability

Science.gov (United States)

Ravert, Russell D.; Zimet, Gregory D.

2009-01-01

Objective: To examine behavioral history, beliefs, and vaccine characteristics as predictors of HIV vaccine acceptability. Methods: Two hundred forty-five US under graduates were surveyed regarding their sexual history, risk beliefs, and likelihood of accepting hypothetical HIV vaccines. Results: Multivariate regression analysis indicated that…

Social Justice and HIV Vaccine Research in the Age of Pre-Exposure Prophylaxis and Treatment as Prevention

Science.gov (United States)

Bailey, Theodore C.; Sugarman, Jeremy

2014-01-01

The advent of pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP) as means of HIV prevention raises issues of justice concerning how most fairly and equitably to apportion resources in support of the burgeoning variety of established HIV treatment and prevention measures and further HIV research, including HIV vaccine research. We apply contemporary approaches to social justice to assess the ethical justification for allocating resources in support of HIV vaccine research given competing priorities to support broad implementation of HIV treatment and prevention measures, including TasP and PrEP. We argue that there is prima facie reason to believe that a safe and effective preventive HIV vaccine would offer a distinct set of ethically significant benefits not provided by current HIV treatment or prevention methods. It is thereby possible to justify continued support for HIV vaccine research despite tension with priorities for treatment, prevention, and other research. We then consider a counter-argument to such a justification based on the uncertainty of successfully developing a safe and effective preventive HIV vaccine. Finally, we discuss how HIV vaccine research might now be ethically designed and conducted given the new preventive options of TasP and PrEP, focusing on the ethically appropriate standard of prevention for HIV vaccine trials. PMID:24033297

IL-4 and IL-13 mediated down-regulation of CD8 expression levels can dampen anti-viral CD8⁺ T cell avidity following HIV-1 recombinant pox viral vaccination.

Science.gov (United States)

Wijesundara, Danushka K; Jackson, Ronald J; Tscharke, David C; Ranasinghe, Charani

2013-09-23

We have shown that mucosal HIV-1 recombinant pox viral vaccination can induce high, avidity HIV-specific CD8(+) T cells with reduced interleukin (IL)-4 and IL-13 expression compared to, systemic vaccine delivery. In the current study how these cytokines act to regulate anti-viral CD8(+) T, cell avidity following HIV-1 recombinant pox viral prime-boost vaccination was investigated. Out of a panel of T cell avidity markers tested, only CD8 expression levels were found to be enhanced on, KdGag197-205 (HIV)-specific CD8(+) T cells obtained from IL-13(-/-), IL-4(-/-) and signal transducer and, activator of transcription of 6 (STAT6)(-/-) mice compared to wild-type (WT) controls following, vaccination. Elevated CD8 expression levels in this instance also correlated with polyfunctionality, (interferon (IFN)-γ, tumour necorsis factor (TNF)-α and IL-2 production) and the avidity of HIVspecific CD8(+) T cells. Furthermore, mucosal vaccination and vaccination with the novel adjuvanted IL-13 inhibitor (i.e. IL-13Rα2) vaccines significantly enhanced CD8 expression levels on HIV-specific CD8(+), T cells, which correlated with avidity. Using anti-CD8 antibodies that blocked CD8 availability on CD8(+), T cells, it was established that CD8 played an important role in increasing HIV-specific CD8(+) T cell avidity and polyfunctionality in IL-4(-/-), IL-13(-/-) and STAT6(-/-) mice compared to WT controls, following vaccination. Collectively, our data demonstrate that IL-4 and IL-13 dampen CD8 expression levels on anti-viral CD8(+) T cells, which can down-regulate anti-viral CD8(+) T cell avidity and, polyfunctionality following HIV-1 recombinant pox viral vaccination. These findings can be exploited to, design more efficacious vaccines not only against HIV-1, but many chronic infections where high, avidity CD8(+) T cells help protection. Copyright © 2013 Elsevier Ltd. All rights reserved.

A study of vaccine-induced immune pressure on breakthrough infections in the Phambili phase 2b HIV-1 vaccine efficacy trial

Science.gov (United States)

Rolland, M.; Magaret, C.A.; Rademeyer, C.; Fiore-Gartland, A.; Edlefsen, P.T.; DeCamp, A.; Ahmed, H.; Ngandu, N.; Larsen, B.B.; Frahm, N.; Marais, J.; Thebus, R.; Geraghty, D.; Hural, J.; Corey, L.; Kublin, J.; Gray, G.; McElrath, M.J.; Mullins, J.I.; Gilbert, P.B.; Williamson, C.

2016-01-01

Introduction The Merck Adenovirus-5 Gag/Pol/Nef HIV-1 subtype-B vaccine evaluated in predominately subtype B epidemic regions (Step Study), while not preventing infection, exerted vaccine-induced immune pressure on HIV-1 breakthrough infections. Here we investigated if the same vaccine exerted immune pressure when tested in the Phambili Phase 2b study in a subtype C epidemic. Materials and methods A sieve analysis, which compares breakthrough viruses from placebo and vaccine arms, was performed on 277 near full-length genomes generated from 23 vaccine and 20 placebo recipients. Vaccine coverage was estimated by computing the percentage of 9-mers that were exact matches to the vaccine insert. Results There was significantly greater protein distances from the vaccine immunogen sequence in Gag (p = 0.045) and Nef (p = 0.021) in viruses infecting vaccine recipients compared to placebo recipients. Twenty-seven putative sites of vaccine-induced pressure were identified (p sieve effect in Step was driven by HLA A*02:01; an allele which was found in low frequency in Phambili participants compared to Step participants. Furthermore, the coverage of the vaccine against subtype C Phambili viruses was 31%, 46% and 14% for Gag, Pol and Nef, respectively, compared to subtype B Step virus coverage of 56%, 61% and 26%, respectively. Discussion This study presents evidence of sieve effects in Gag and Nef; however could not confirm effects on specific amino acid sites. We propose that this weaker signal of vaccine immune pressure detected in the Phambili study compared to the Step study may have been influenced by differences in host genetics (HLA allele frequency) and reduced impact of vaccine-induced immune responses due to mismatch between the viral subtype in the vaccine and infecting subtypes. PMID:27756485

Is a HIV vaccine a viable option and at what price? An economic evaluation of adding HIV vaccination into existing prevention programs in Thailand

OpenAIRE

Leelahavarong, Pattara; Teerawattananon, Yot; Werayingyong, Pitsaphun; Akaleephan, Chutima; Premsri, Nakorn; Namwat, Chawetsan; Peerapatanapokin, Wiwat; Tangcharoensathien, Viroj

2011-01-01

Abstract Background This study aims to determine the maximum price at which HIV vaccination is cost-effective in the Thai healthcare setting. It also aims to identify the relative importance of vaccine characteristics and risk behavior changes among vaccine recipients to determine how they affect this cost-effectiveness. Methods A semi-Markov model was developed to estimate the costs and health outcomes of HIV prevention programs combined with HIV vaccination in comparison to the existing HIV...

Modeling HIV vaccines in Brazil: assessing the impact of a future HIV vaccine on reducing new infections, mortality and number of people receiving ARV.

Directory of Open Access Journals (Sweden)

Maria Goretti P Fonseca

2010-07-01

Full Text Available The AIDS epidemic in Brazil remains concentrated in populations with high vulnerability to HIV infection, and the development of an HIV vaccine could make an important contribution to prevention. This study modeled the HIV epidemic and estimated the potential impact of an HIV vaccine on the number of new infections, deaths due to AIDS and the number of people receiving ARV treatment, under various scenarios.The historical HIV prevalence was modeled using Spectrum and projections were made from 2010 to 2050 to study the impact of an HIV vaccine with 40% to 70% efficacy, and 80% coverage of adult population, specific groups such as MSM, IDU, commercial sex workers and their partners, and 15 year olds. The possibility of disinhibition after vaccination, neglecting medium- and high-risk groups, and a disease-modifying vaccine were also considered. The number of new infections and deaths were reduced by 73% and 30%, respectively, by 2050, when 80% of adult population aged 15-49 was vaccinated with a 40% efficacy vaccine. Vaccinating medium- and high-risk groups reduced new infections by 52% and deaths by 21%. A vaccine with 70% efficacy produced a great decline in new infections and deaths. Neglecting medium- and high-risk population groups as well as disinhibition of vaccinated population reduced the impact or even increased the number of new infections. Disease-modifying vaccine also contributed to reducing AIDS deaths, the need for ART and new HIV infections.Even in a country with a concentrated epidemic and high levels of ARV coverage, such as Brazil, moderate efficacy vaccines as part of a comprehensive package of treatment and prevention could have a major impact on preventing new HIV infections and AIDS deaths, as well as reducing the number of people on ARV. Targeted vaccination strategies may be highly effective and cost-beneficial.

HIV vaccine development: would more (public) money bring quicker results?

Science.gov (United States)

Winsbury, R

1999-01-01

Globally, $200-250 million/year are devoted to HIV vaccine research. Most of those funds pay for basic research rather than product development. Moreover, most of the funds are aimed at the HIV strain commonly found in the US and Europe, and not at the strains common to Africa and other developing countries. While US President Bill Clinton set in 1997 a 10-year target for the development of an HIV vaccine, that target date is looking increasingly unlikely. International vaccine and pharmaceutical companies typically drive vaccine research and development. However, concern over the ultimate profitability of developing and marketing an HIV vaccine, and the fear of major litigation should an eventual vaccine go awry have caused such firms to shy away from investing large amounts of money into HIV vaccine development. These companies somehow have to be attracted back into the field. A World Bank special task force is slated to present its report by mid-1999 on possible funding mechanisms to promote HIV vaccine development. It remains to be resolved whether public funds could and should be used, perhaps through a pooled international vaccine development fund. 2 new International AIDS Vaccine Initiative projects are described.

Is an HIV vaccine possible?

OpenAIRE

Wilson,Nancy A.; Watkins,David I.

2009-01-01

The road to the discovery of a vaccine for HIV has been arduous and will continue to be difficult over the ensuing twenty years. Most vaccines are developed by inducing neutralizing antibodies against the target pathogen or by using attenuated strains of the particular pathogen to engender a variety of protective immune responses. Unfortunately, simple methods of generating anti-HIV antibodies have already failed in a phase III clinical trial. While attenuated SIV variants work well against h...

The Case for Adolescent HIV Vaccination in South Africa

OpenAIRE

Moodley, Nishila; Gray, Glenda; Bertram, Melanie

2016-01-01

Abstract Despite comprising 0.7% of the world population, South Africa is home to 18% of the global human immunodeficiency virus (HIV) prevalence. Unyielding HIV subepidemics among adolescents threaten national attempts to curtail the disease burden. Should an HIV vaccine become available, establishing its point of entry into the health system becomes a priority. This study assesses the impact of school-based HIV vaccination and explores how variations in vaccine characteristics affect cost-e...

DNA/MVA Vaccines for HIV/AIDS

Directory of Open Access Journals (Sweden)

Smita S. Iyer

2014-02-01

Full Text Available Since the initial proof-of-concept studies examining the ability of antigen-encoded plasmid DNA to serve as an immunogen, DNA vaccines have evolved as a clinically safe and effective platform for priming HIV-specific cellular and humoral responses in heterologous “prime-boost” vaccination regimens. Direct injection of plasmid DNA into the muscle induces T- and B-cell responses against foreign antigens. However, the insufficient magnitude of this response has led to the development of approaches for enhancing the immunogenicity of DNA vaccines. The last two decades have seen significant progress in the DNA-based vaccine platform with optimized plasmid constructs, improved delivery methods, such as electroporation, the use of molecular adjuvants and novel strategies combining DNA with viral vectors and subunit proteins. These innovations are paving the way for the clinical application of DNA-based HIV vaccines. Here, we review preclinical studies on the DNA-prime/modified vaccinia Ankara (MVA-boost vaccine modality for HIV. There is a great deal of interest in enhancing the immunogenicity of DNA by engineering DNA vaccines to co-express immune modulatory adjuvants. Some of these adjuvants have demonstrated encouraging results in preclinical and clinical studies, and these data will be examined, as well.

HIV-1 envelope glycoprotein

Science.gov (United States)

Caulfield, Michael; Cupo, Albert; Dean, Hansi; Hoffenberg, Simon; King, C. Richter; Klasse, P. J.; Marozsan, Andre; Moore, John P.; Sanders, Rogier W.; Ward, Andrew; Wilson, Ian; Julien, Jean-Philippe

2017-08-22

The present application relates to novel HIV-1 envelope glycoproteins, which may be utilized as HIV-1 vaccine immunogens, and antigens for crystallization, electron microscopy and other biophysical, biochemical and immunological studies for the identification of broad neutralizing antibodies. The present invention encompasses the preparation and purification of immunogenic compositions, which are formulated into the vaccines of the present invention.

Scientific and regulatory challenges in evaluating clinical trial protocols for HIV-1/AIDS vaccines - A review from a regulatory perspective.

Science.gov (United States)

Sheets, Rebecca L; Zhou, TieQun; Knezevic, Ivana

2016-03-01

Clinical development of prophylactic HIV/AIDS vaccines presents many scientific challenges that result in challenges for regulators reviewing clinical trial applications (CTAs). The World Health Organization (WHO) has the responsibility to provide technical support to these regulators. The search for an HIV/AIDS vaccine will only succeed through well-designed, -conducted and -controlled human efficacy studies reviewed and approved by regulators in countries worldwide, particularly in countries where the epidemic has hit hardest, such as in sub-Saharan Africa and Asia. This review summarizes the current candidates in development and focuses on challenges regulators face when reviewing CTAs, such as the evolving landscape of "standard of prevention," trials in adolescents, adaptive trial designs, correlates of protection and their analysis, and access to successful vaccines. There are many unknowns in the field of HIV/AIDS vaccine development and often, there is not a clear right or wrong approach because of the scientific challenges described in this review. Consequently, regulators should not feel that decisions need be made in isolation, when there are many available international collaborative efforts and opportunities to seek expert advice. The WHO provides many such opportunities and support to regulators across the globe. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

A recombinant mimetics of the HIV-1 gp41 prehairpin fusion intermediate fused with human IgG Fc fragment elicits neutralizing antibody response in the vaccinated mice

International Nuclear Information System (INIS)

Qi, Zhi; Pan, Chungen; Lu, Hong; Shui, Yuan; Li, Lin; Li, Xiaojuan; Xu, Xueqing; Liu, Shuwen; Jiang, Shibo

2010-01-01

Research highlights: → One recombinant mimetics of gp41 prehairpin fusion intermediate (PFI) consisting of gp41 N46 sequence, foldon and IgG Fc, designated N46FdFc, was expressed. → N46FdFc-induced antibodies in mice that neutralized HIV-1 infection, inhibited PIE7 binding to PFI, blocked gp41 six-helix bundle formation, and suppressed HIV-1 mediated cell-cell fusion. → These findings provide an important clue for developing recombinant gp41 PFI mimetics-based HIV vaccines. -- Abstract: HIV-1 gp41 prehairpin fusion intermediate (PFI) composed of three N-terminal heptad repeats (NHR) plays a crucial role in viral fusion and entry and represents an attractive target for anti-HIV therapeutics (e.g., enfuvirtide) and vaccines. In present study, we constructed and expressed two recombinant gp41 PFI mimetics, designated N46Fd and N46FdFc. N46Fd consists of N46 (residues 536-581) in gp41 NHR and foldon (Fd), a trimerization motif. N46FdFc is composed of N46Fd fused with human IgG Fc fragment as an immunoenhancer. We immunized mice with N46 peptide, N46Fd and N46FdFc, respectively, and found that only N46FdFc elicited neutralizing antibody response in mice against infection by HIV-1 strains IIIB (clade B, X4), 92US657 (clade B, R5), and 94UG103 (clade A, X4R5). Anti-N46FdFc antibodies inhibited PIE7 binding to PFI, blocked gp41 six-helix bundle formation, and suppressed HIV-1 mediated cell-cell fusion. These findings provide an important clue for developing recombinant gp41 PFI mimetics-based HIV vaccines.

Safety and immunogenicity of HIV-1 Tat toxoid in immunocompromised HIV-1-infected patients.

Science.gov (United States)

Gringeri, A; Santagostino, E; Muça-Perja, M; Mannucci, P M; Zagury, J F; Bizzini, B; Lachgar, A; Carcagno, M; Rappaport, J; Criscuolo, M; Blattner, W; Burny, A; Gallo, R C; Zagury, D

1998-01-01

To antagonize the deleterious effects of the HIV-1 toxin extracellular Tat on uninfected immune cells, we developed a new strategy of anti-HIV-1 vaccine using an inactivated but immunogenic Tat (Tat toxoid). Tat toxoid has been assayed for safety and immunogenicity in seropositive patients. The phase I vaccine clinical trial testing Tat toxoid preparation in Seppic Isa 51 oil adjuvant was performed on 14 HIV-1-infected asymptomatic although biologically immunocompromised individuals (500-200 CD4+ cells/mm3). Following as many as 8 injections, no clinical defects were observed. All patients exhibited an antibody (Ab) response to Tat, and some had cell-mediated immunity (CMI) as evaluated by skin test in vivo and T-cell proliferation in vitro. These results provide initial evidence of safety and potency of Tat toxoid vaccination in HIV-1-infected individuals.

Extended Follow-up Confirms Early Vaccine-Enhanced Risk of HIV Acquisition and Demonstrates Waning Effect Over Time Among Participants in a Randomized Trial of Recombinant Adenovirus HIV Vaccine (Step Study)

Science.gov (United States)

Duerr, Ann; Huang, Yunda; Buchbinder, Susan; Coombs, Robert W.; Sanchez, Jorge; del Rio, Carlos; Casapia, Martin; Santiago, Steven; Gilbert, Peter; Corey, Lawrence; Robertson, Michael N.

2012-01-01

Background. The Step Study tested whether an adenovirus serotype 5 (Ad5)–vectored human immunodeficiency virus (HIV) vaccine could prevent HIV acquisition and/or reduce viral load set-point after infection. At the first interim analysis, nonefficacy criteria were met. Vaccinations were halted; participants were unblinded. In post hoc analyses, more HIV infections occurred in vaccinees vs placebo recipients in men who had Ad5-neutralizing antibodies and/or were uncircumcised. Follow-up was extended to assess relative risk of HIV acquisition in vaccinees vs placebo recipients over time. Methods. We used Cox proportional hazard models for analyses of vaccine effect on HIV acquisition and vaccine effect modifiers, and nonparametric and semiparametric methods for analysis of constancy of relative risk over time. Results. One hundred seventy-two of 1836 men were infected. The adjusted vaccinees vs placebo recipients hazard ratio (HR) for all follow-up time was 1.40 (95% confidence interval [CI], 1.03–1.92; P = .03). Vaccine effect differed by baseline Ad5 or circumcision status during first 18 months, but neither was significant for all follow-up time. The HR among uncircumcised and/or Ad5-seropositive men waned with time since vaccination. No significant vaccine-associated risk was seen among circumcised, Ad5-negative men (HR, 0.97; P = 1.0) over all follow-up time. Conclusions. The vaccine-associated risk seen in interim analysis was confirmed but waned with time from vaccination. Clinical Trials Registration. NCT00095576. PMID:22561365

Ethical considerations in HIV prevention and vaccine research in resource-limited settings.

Science.gov (United States)

Garner, Samual A; Anude, Chuka J; Adams, Elizabeth; Dawson, Liza

2014-09-01

HIV prevention research has been facing increasing ethical and operational challenges. Factors influencing the design and conduct of HIV prevention trials include a rapidly changing evidence base, new biomedical prevention methods and modalities being tested, a large diversity of countries, sites and populations affected by HIV and participating in trials, and challenges of developing and making available products that will be feasible and affordable for at-risk populations. To discuss these challenges, a meeting, Ethical considerations around novel combination prevention modalities in HIV prevention and vaccine trials in resource-limited settings, was convened by NIH/NIAID/Division of AIDS on April 22-23, 2013. Several themes emerged from the meeting: (1) because of both trial design and ethical complexities, choosing prevention packages and designing combination prevention research trials will need to be evaluated on a case by case basis in different clinical trials, countries, and health systems; (2) multilevel stakeholder engagement from the beginning is vital to a fair and transparent process and also to designing ethical and relevant trials; (3) research should generally be responsive to a host country's needs, and sponsors and stakeholders should work together to address potential barriers to future access; and finally, (4) another meeting including a broader group of stakeholders is needed to address many of the outstanding ethical issues raised by this meeting. We offer an overview of the meeting and the key discussion points and recommendations to help guide the design and conduct of future HIV prevention and vaccine research in resource-limited settings.

Structure-Based Design of a Soluble Prefusion-Closed HIV-1 Env Trimer with Reduced CD4 Affinity and Improved Immunogenicity

Energy Technology Data Exchange (ETDEWEB)

Chuang, Gwo-Yu; Geng, Hui; Pancera, Marie; Xu, Kai; Cheng, Cheng; Acharya, Priyamvada; Chambers, Michael; Druz, Aliaksandr; Tsybovsky, Yaroslav; Wanninger, Timothy G.; Yang, Yongping; Doria-Rose, Nicole A.; Georgiev, Ivelin S.; Gorman, Jason; Joyce, M.Gordon; O; Dell, Sijy; Zhou, Tongqing; McDermott, Adrian B.; Mascola, John R.; Kwong, Peter D. (NIH); (FNL)

2017-03-08

The HIV-1 envelope (Env) trimer is a target for vaccine design as well as a conformational machine that facilitates virus entry by transitioning between prefusion-closed, CD4-bound, and coreceptor-bound conformations by transitioning into a postfusion state. Vaccine designers have sought to restrict the conformation of the HIV-1 Env trimer to its prefusion-closed state as this state is recognized by most broadly neutralizing, but not nonneutralizing, antibodies. We previously identified a disulfide bond, I201C-A433C (DS), which stabilizes Env in the vaccine-desired prefusion-closed state. When placed into the context of BG505 SOSIP.664, a soluble Env trimer mimic developed by Sanders, Moore, and colleagues, the engineered DS-SOSIP trimer showed reduced conformational triggering by CD4. Here, we further stabilize DS-SOSIP through a combination of structure-based design and 96-well-based expression and antigenic assessment. From 103 designs, we identified one, named DS-SOSIP.4mut, with four additional mutations at the interface of potentially mobile domains of the prefusion-closed structure. We also determined the crystal structures of DS-SOSIP.4mut at 4.1-Å resolution and of an additional DS-SOSIP.6mut variant at 4.3-Å resolution, and these confirmed the formation of engineered disulfide bonds. Notably, DS-SOSIP.4mut elicited a higher ratio of tier 2 autologous titers versus tier 1 V3-sensitive titers than BG505 SOSIP.664. DS-SOSIP.4mut also showed reduced recognition of CD4 and increased thermostability. The improved antigenicity, thermostability, and immunogenicity of DS-SOSIP.4mut suggest utility as an immunogen or a serologic probe; moreover, the specific four alterations identified here, M154, M300, M302, and L320 (4mut), can also be transferred to other HIV-1 Env trimers of interest to improve their properties.

IMPORTANCEOne approach to elicit broadly neutralizing antibodies against HIV-1 is to stabilize the

Conceptual framework for behavioral and social science in HIV vaccine clinical research.

Science.gov (United States)

Lau, Chuen-Yen; Swann, Edith M; Singh, Sagri; Kafaar, Zuhayr; Meissner, Helen I; Stansbury, James P

2011-10-13

HIV vaccine clinical research occurs within a context where biomedical science and social issues are interlinked. Previous HIV vaccine research has considered behavioral and social issues, but often treated them as independent of clinical research processes. Systematic attention to the intersection of behavioral and social issues within a defined clinical research framework is needed to address gaps, such as those related to participation in trials, completion of trials, and the overall research experience. Rigorous attention to these issues at project inception can inform trial design and conduct by matching research approaches to the context in which trials are to be conducted. Conducting behavioral and social sciences research concurrent with vaccine clinical research is important because it can help identify potential barriers to trial implementation, as well as ultimate acceptance and dissemination of trial results. We therefore propose a conceptual framework for behavioral and social science in HIV vaccine clinical research and use examples from the behavioral and social science literature to demonstrate how the model can facilitate identification of significant areas meriting additional exploration. Standardized use of the conceptual framework could improve HIV vaccine clinical research efficiency and relevance. Published by Elsevier Ltd.

Immunization with Clinical HIV-1 Env Proteins Induces Broad Antibody Dependent Cellular Cytotoxicity-Mediating Antibodies in a Rabbit Vaccination Model.

Science.gov (United States)

Karlsson, Ingrid; Borggren, Marie; Jensen, Sanne Skov; Heyndrickx, Leo; Stewart-Jones, Guillaume; Scarlatti, Gabriella; Fomsgaard, Anders

2017-11-17

The induction of both neutralizing antibodies and non-neutralizing antibodies with effector functions, for example, antibody-dependent cellular cytotoxicity (ADCC), is desired in the search for effective vaccines against HIV-1. In the pursuit of novel immunogens capable of inducing an efficient antibody response, rabbits were immunized with selected antigens using different prime-boost strategies. We immunized 35 different groups of rabbits with Env antigens from clinical HIV-1 subtypes A and B, including immunization with DNA alone, protein alone, and DNA prime with protein boost. The rabbit sera were screened for ADCC activity using a GranToxiLux-based assay with human peripheral blood mononuclear cells as effector cells and CEM.NKR CCR5 cells coated with HIV-1 envelope as target cells. The groups with the highest ADCC activity were further characterized for cross-reactivity between HIV-1 subtypes. The immunogen inducing the most potent and broadest ADCC response was a trimeric gp140. The ADCC activity was highest against the HIV-1 subtype corresponding to the immunogen. The ADCC activity did not necessarily reflect neutralizing activity in the pseudovirus-TZMbl assay, but there was an overall correlation between the two antiviral activities. We present a rabbit vaccination model and an assay suitable for screening HIV-1 vaccine candidates for the induction of ADCC-mediating antibodies in addition to neutralizing antibodies. The antigens and/or immunization strategies capable of inducing antibodies with ADCC activity did not necessarily induce neutralizing activity and vice versa. Nevertheless, we identified vaccine candidates that were able to concurrently induce both types of responses and that had ADCC activity that was cross-reactive between different subtypes. When searching for an effective vaccine candidate, it is important to evaluate the antibody response using a model and an assay measuring the desired function.

Population immunity to measles virus and the effect of HIV-1 infection after a mass measles vaccination campaign in Lusaka, Zambia: a cross-sectional survey.

Science.gov (United States)

Lowther, Sara A; Curriero, Frank C; Kalish, Brian T; Shields, Timothy M; Monze, Mwaka; Moss, William J

2009-03-21

Measles control efforts are hindered by challenges in sustaining high vaccination coverage, waning immunity in HIV-1-infected children, and clustering of susceptible individuals. Our aim was to assess population immunity to measles virus after a mass vaccination campaign in a region with high HIV prevalence. 3 years after a measles supplemental immunisation activity (SIA), we undertook a cross-sectional survey in Lusaka, Zambia. Households were randomly selected from a satellite image. Children aged 9 months to 5 years from selected households were eligible for enrolment. A questionnaire was administered to the children's caregivers to obtain information about measles vaccination history and history of measles. Oral fluid samples were obtained from children and tested for antibodies to measles virus and HIV-1 by EIA. 1015 children from 668 residences provided adequate specimens. 853 (84%) children had a history of measles vaccination according to either caregiver report or immunisation card. 679 children (67%) had antibodies to measles virus, and 64 (6%) children had antibodies to HIV-1. Children with antibodies to HIV-1 were as likely to have no history of measles vaccination as those without antibodies to HIV-1 (odds ratio [OR] 1.17, 95% CI 0.57-2.41). Children without measles antibodies were more likely to have never received measles vaccine than those with antibodies (adjusted OR 2.50, 1.69-3.71). In vaccinated children, 33 (61%) of 54 children with antibodies to HIV-1 also had antibodies to measles virus, compared with 568 (71%) of 796 children without antibodies to HIV-1 (p=0.1). 3 years after an SIA, population immunity to measles was insufficient to interrupt measles virus transmission. The use of oral fluid and satellite images for sampling are potential methods to assess population immunity and the timing of SIAs.

In vivo electroporation enhances the immunogenicity of an HIV-1 DNA vaccine candidate in healthy volunteers.

Directory of Open Access Journals (Sweden)

Sandhya Vasan

Full Text Available DNA-based vaccines have been safe but weakly immunogenic in humans to date.We sought to determine the safety, tolerability, and immunogenicity of ADVAX, a multigenic HIV-1 DNA vaccine candidate, injected intramuscularly by in vivo electroporation (EP in a Phase-1, double-blind, randomized placebo-controlled trial in healthy volunteers. Eight volunteers each received 0.2 mg, 1 mg, or 4 mg ADVAX or saline placebo via EP, or 4 mg ADVAX via standard intramuscular injection at weeks 0 and 8. A third vaccination was administered to eleven volunteers at week 36. EP was safe, well-tolerated and considered acceptable for a prophylactic vaccine. EP delivery of ADVAX increased the magnitude of HIV-1-specific cell mediated immunity by up to 70-fold over IM injection, as measured by gamma interferon ELISpot. The number of antigens to which the response was detected improved with EP and increasing dosage. Intracellular cytokine staining analysis of ELISpot responders revealed both CD4+ and CD8+ T cell responses, with co-secretion of multiple cytokines.This is the first demonstration in healthy volunteers that EP is safe, tolerable, and effective in improving the magnitude, breadth and durability of cellular immune responses to a DNA vaccine candidate.ClinicalTrials.gov NCT00545987.

Isotype Diversification of IgG Antibodies to HIV Gag Proteins as a Therapeutic Vaccination Strategy for HIV Infection.

Science.gov (United States)

French, Martyn A; Abudulai, Laila N; Fernandez, Sonia

2013-08-09

The development of vaccines to treat and prevent human immunodeficiency virus (HIV) infection has been hampered by an incomplete understanding of "protective" immune responses against HIV. Natural control of HIV-1 infection is associated with T-cell responses against HIV-1 Gag proteins, particularly CD8⁺ T-cell responses restricted by "protective" HLA-B alleles, but other immune responses also contribute to immune control. These immune responses appear to include IgG antibodies to HIV-1 Gag proteins, interferon-a-dependant natural killer (NK) cell responses and plasmacytoid dendritic cell (pDC) responses. Here, it is proposed that isotype diversification of IgG antibodies against HIV-1 Gag proteins, to include IgG2, as well as IgG3 and IgG1 antibodies, will broaden the function of the antibody response and facilitate accessory cell responses against HIV-1 by NK cells and pDCs. We suggest that this should be investigated as a vaccination strategy for HIV-1 infection.

Isotype Diversification of IgG Antibodies to HIV Gag Proteins as a Therapeutic Vaccination Strategy for HIV Infection

Directory of Open Access Journals (Sweden)

Sonia Fernandez

2013-08-01

Full Text Available The development of vaccines to treat and prevent human immunodeficiency virus (HIV infection has been hampered by an incomplete understanding of “protective” immune responses against HIV. Natural control of HIV-1 infection is associated with T-cell responses against HIV-1 Gag proteins, particularly CD8+ T-cell responses restricted by “protective” HLA-B alleles, but other immune responses also contribute to immune control. These immune responses appear to include IgG antibodies to HIV-1 Gag proteins, interferon-a-dependant natural killer (NK cell responses and plasmacytoid dendritic cell (pDC responses. Here, it is proposed that isotype diversification of IgG antibodies against HIV-1 Gag proteins, to include IgG2, as well as IgG3 and IgG1 antibodies, will broaden the function of the antibody response and facilitate accessory cell responses against HIV-1 by NK cells and pDCs. We suggest that this should be investigated as a vaccination strategy for HIV-1 infection.

Antibody Responses with Fc-Mediated Functions after Vaccination of HIV-Infected Subjects with Trivalent Influenza Vaccine

DEFF Research Database (Denmark)

Kristensen, Anne B; Lay, William N; Ana-Sosa-Batiz, Fernanda

2016-01-01

to immunize this at-risk group. IMPORTANCE: Infection with HIV is associated with increasing disease severity following influenza infections, and annual influenza vaccinations are recommended for this target group. However, HIV-infected individuals respond relatively poorly to vaccination compared to healthy......This study seeks to assess the ability of seasonal trivalent inactivated influenza vaccine (TIV) to induce nonneutralizing antibodies (Abs) with Fc-mediated functions in HIV-uninfected and HIV-infected subjects. Functional influenza-specific Ab responses were studied in 30 HIV-negative and 27 HIV......-positive subjects immunized against seasonal influenza. All 57 subjects received the 2015 TIV. Fc-mediated antihemagglutinin (anti-HA) Ab activity was measured in plasma before and 4 weeks after vaccination using Fc-receptor-binding assays, NK cell activation assays, and phagocytosis assays. At baseline, the HIV...

Vaccination of HIV-infected pregnant women: implications for protection of their young infants.

Science.gov (United States)

Dangor, Ziyaad; Nunes, Marta C; Kwatra, Gaurav; Lala, Sanjay G; Madhi, Shabir A

2017-01-01

The prevention of mother to child transmission of HIV has resulted in reduced burden of pediatric HIV-infection, but the prevalence of maternal HIV infection remains high in sub-Saharan African countries. HIV-exposed-uninfected infants have an increased risk of morbidity and mortality due to infectious diseases than HIV-unexposed infants, particularly during the first six months of life, which in part might be due to lower levels of pathogen-specific protective antibodies acquired transplacentally from their mothers. This could be mitigated by vaccinating pregnant women to boost antibody levels; although vaccine responses among HIV-infected pregnant women might differ compared to HIV-uninfected women. We reviewed studies that compared natural and vaccine-induced antibody levels to different epitopes between HIV-infected and HIV-uninfected pregnant women. Most studies reported lower baseline/pre-vaccination antibody levels in HIV-infected pregnant women, which may not be reversed by antiretroviral therapy during pregnancy. There were only few studies on vaccination of HIV-infected pregnant women, mainly on influenza virus and group B Streptococcus (GBS) vaccines. Immunogenicity studies on influenza vaccines indicated that HIV-infected pregnant women had lower vaccine induced hemagglutination inhibition antibody titers and a decreased likelihood of seroconversion compared to HIV-uninfected women; and while higher CD4+ T-lymphocyte levels were associated with better immune responses to vaccination, HIV viral load was not associated with responses. Furthermore, infants born to influenza vaccinated HIV-infected pregnant women also had lower antibody levels and a lower proportion of HIV-exposed infants had titers above the putative correlate of protection compared to HIV-unexposed infants. The immunogenicity of a CRM 197 -conjugated trivalent GBS vaccine was also lower in HIV-infected pregnant women compared to HIV-uninfected women, irrespective of CD4+ T

Volunteer motivators for participating in HIV vaccine clinical trials in Nairobi, Kenya.

Science.gov (United States)

Nyaoke, Borna A; Mutua, Gaudensia N; Sajabi, Rose; Nyasani, Delvin; Mureithi, Marianne W; Anzala, Omu A

2017-01-01

1.5 million Kenyans are living with HIV/AIDS as per 2015 estimates. Though there is a notable decline in new HIV infections, continued effort is still needed to develop an efficacious, accessible and affordable HIV vaccine. HIV vaccine clinical trials bear risks, hence a need to understand volunteer motivators for enrolment, retention and follow-up. Understanding the factors that motivate volunteers to participate in a clinical trial can help to strategize, refine targeting and thus increase enrolment of volunteers in future HIV vaccine clinical trials. The health belief model classifies motivators into social benefits such as 'advancing research' and collaboration with science, and personal benefits such as health benefits and financial interests. A thematic analysis was carried out on data obtained from four HIV clinical trials conducted at KAVI-Institute of Clinical Research in Nairobi Kenya from 2009 to 2015. Responses were obtained from a Questionnaire administered to the volunteers during their screening visit at the research site. Of the 281 healthy, HIV-uninfected volunteers participating in this study; 38% were motivated by personal benefits including, 31% motivated by health benefits and 7% motivated by possible financial gains. In addition, 62% of the volunteers were motivated by social benefits with 20% of who were seeking to help their family/society/world while 42% were interested in advancing research. The majority of volunteers in the HIV vaccine trials at our site were motivated by social benefits, suggesting that altruism can be a major contributor to participation in HIV vaccine studies. Personal benefits were a secondary motivator for the volunteers. The motivators to volunteer in HIV clinical trials were similar across ages, education level and gender. Education on what is needed (including volunteer participation) to develop an efficacious vaccine could be the key to greater volunteer motivation to participate in HIV vaccine clinical trials.

Volunteer motivators for participating in HIV vaccine clinical trials in Nairobi, Kenya.

Directory of Open Access Journals (Sweden)

Borna A Nyaoke

Full Text Available 1.5 million Kenyans are living with HIV/AIDS as per 2015 estimates. Though there is a notable decline in new HIV infections, continued effort is still needed to develop an efficacious, accessible and affordable HIV vaccine. HIV vaccine clinical trials bear risks, hence a need to understand volunteer motivators for enrolment, retention and follow-up. Understanding the factors that motivate volunteers to participate in a clinical trial can help to strategize, refine targeting and thus increase enrolment of volunteers in future HIV vaccine clinical trials. The health belief model classifies motivators into social benefits such as 'advancing research' and collaboration with science, and personal benefits such as health benefits and financial interests.A thematic analysis was carried out on data obtained from four HIV clinical trials conducted at KAVI-Institute of Clinical Research in Nairobi Kenya from 2009 to 2015. Responses were obtained from a Questionnaire administered to the volunteers during their screening visit at the research site.Of the 281 healthy, HIV-uninfected volunteers participating in this study; 38% were motivated by personal benefits including, 31% motivated by health benefits and 7% motivated by possible financial gains. In addition, 62% of the volunteers were motivated by social benefits with 20% of who were seeking to help their family/society/world while 42% were interested in advancing research.The majority of volunteers in the HIV vaccine trials at our site were motivated by social benefits, suggesting that altruism can be a major contributor to participation in HIV vaccine studies. Personal benefits were a secondary motivator for the volunteers. The motivators to volunteer in HIV clinical trials were similar across ages, education level and gender. Education on what is needed (including volunteer participation to develop an efficacious vaccine could be the key to greater volunteer motivation to participate in HIV vaccine

Immune response after one or two doses of pandemic influenza A (H1N1) monovalent, AS03-adjuvanted vaccine in HIV infected adults

DEFF Research Database (Denmark)

Bybeck Nielsen, Allan; Nielsen, Henriette Schjønning; Nielsen, Lars

2012-01-01

INTRODUCTION: Continued research is needed to evaluate and improve the immunogenicity of influenza vaccines in HIV infected patients. We aimed to determine the antibody responses after one or two doses of the AS03-adjuvanted pandemic influenza A (H1N1) vaccine in HIV infected patients. METHOD......: Following the influenza season 2009/2010, 219 HIV infected patients were included and divided into three groups depending on whether they received none (n=60), one (n=31) or two (n=128) doses of pandemic influenza A (H1N1) vaccine. At inclusion, antibody titers for all patients were analyzed and compared...... to pre-pandemic antibody titers analyzed from serum samples in a local storage facility. RESULTS: 4-9 months after a single immunization, we found a seroprotection rate of 77.4% and seroconversion rate of 67.7%. After two immunizations the rates increased significantly to seroprotection rate of 97...

Analysis of V2 antibody responses induced in vaccinees in the ALVAC/AIDSVAX HIV-1 vaccine efficacy trial.

Directory of Open Access Journals (Sweden)

Susan Zolla-Pazner

Full Text Available The RV144 clinical trial of a prime/boost immunizing regimen using recombinant canary pox (ALVAC-HIV and two gp120 proteins (AIDSVAX B and E was previously shown to have a 31.2% efficacy rate. Plasma specimens from vaccine and placebo recipients were used in an extensive set of assays to identify correlates of HIV-1 infection risk. Of six primary variables that were studied, only one displayed a significant inverse correlation with risk of infection: the antibody (Ab response to a fusion protein containing the V1 and V2 regions of gp120 (gp70-V1V2. This finding prompted a thorough examination of the results generated with the complete panel of 13 assays measuring various V2 Abs in the stored plasma used in the initial pilot studies and those used in the subsequent case-control study. The studies revealed that the ALVAC-HIV/AIDSVAX vaccine induced V2-specific Abs that cross-react with multiple HIV-1 subgroups and recognize both conformational and linear epitopes. The conformational epitope was present on gp70-V1V2, while the predominant linear V2 epitope mapped to residues 165-178, immediately N-terminal to the putative α4β7 binding motif in the mid-loop region of V2. Odds ratios (ORs were calculated to compare the risk of infection with data from 12 V2 assays, and in 11 of these, the ORs were ≤1, reaching statistical significance for two of the variables: Ab responses to gp70-V1V2 and to overlapping V2 linear peptides. It remains to be determined whether anti-V2 Ab responses were directly responsible for the reduced infection rate in RV144 and whether anti-V2 Abs will prove to be important with other candidate HIV vaccines that show efficacy, however, the results support continued dissection of Ab responses to the V2 region which may illuminate mechanisms of protection from HIV-1 infection and may facilitate the development of an effective HIV-1 vaccine.

HIV-1 p24(gag derived conserved element DNA vaccine increases the breadth of immune response in mice.

Directory of Open Access Journals (Sweden)

Viraj Kulkarni

Full Text Available Viral diversity is considered a major impediment to the development of an effective HIV-1 vaccine. Despite this diversity, certain protein segments are nearly invariant across the known HIV-1 Group M sequences. We developed immunogens based on the highly conserved elements from the p24(gag region according to two principles: the immunogen must (i include strictly conserved elements of the virus that cannot mutate readily, and (ii exclude both HIV regions capable of mutating without limiting virus viability, and also immunodominant epitopes located in variable regions. We engineered two HIV-1 p24(gag DNA immunogens that express 7 highly Conserved Elements (CE of 12-24 amino acids in length and differ by only 1 amino acid in each CE ('toggle site', together covering >99% of the HIV-1 Group M sequences. Altering intracellular trafficking of the immunogens changed protein localization, stability, and also the nature of elicited immune responses. Immunization of C57BL/6 mice with p55(gag DNA induced poor, CD4(+ mediated cellular responses, to only 2 of the 7 CE; in contrast, vaccination with p24CE DNA induced cross-clade reactive, robust T cell responses to 4 of the 7 CE. The responses were multifunctional and composed of both CD4(+ and CD8(+ T cells with mature cytotoxic phenotype. These findings provide a method to increase immune response to universally conserved Gag epitopes, using the p24CE immunogen. p24CE DNA vaccination induced humoral immune responses similar in magnitude to those induced by p55(gag, which recognize the virus encoded p24(gag protein. The inclusion of DNA immunogens composed of conserved elements is a promising vaccine strategy to induce broader immunity by CD4(+ and CD8(+ T cells to additional regions of Gag compared to vaccination with p55(gag DNA, achieving maximal cross-clade reactive cellular and humoral responses.

Decreased HIV-specific T-regulatory responses are associated with effective DC-vaccine induced immunity.

Directory of Open Access Journals (Sweden)

Vedran Brezar

2015-03-01

Full Text Available The role of regulatory T cells (Tregs in vaccination has been poorly investigated. We have reported that vaccination with ex vivo-generated dendritic-cells (DC loaded with HIV-lipopeptides (LIPO-5-DC vaccine in HIV-infected patients was well tolerated and highly immunogenic. These responses and their relation to viral replication following analytical treatment interruption (ATI were variable. Here, we investigated whether the presence of HIV-specific Tregs might explain these differences. Co-expression of CD25, CD134, CD39 and FoxP3 was used to delineate both antigen-specific Tregs and effectors T cells (Teffs. Median LIPO-5 specific-CD25+CD134+ polyfunctional T cells increased from 0.1% (IQR 0-0.3 before vaccination (week -4 to 2.1% (IQR 1.1-3.9 at week 16 following 4 immunizations (p=0.001 and were inversely correlated with maximum viral load following ATI (r=-0.77, p=0.001. Vaccinees who displayed lower levels of HIV-specific CD4+CD134+CD25+CD39+FoxP3+ Tregs responded better to the LIPO-5-DC vaccine. After vaccination, the frequency of HIV-specific Tregs decreased (from 69.3 at week -4 to 31.7% at week 16 and inversely correlated with HIV-specific IFN-γ-producing cells (r=-0.64, p=0.002. We show that therapeutic immunization skewed the HIV-specific response from regulatory to effector phenotype which impacts on the magnitude of viral replication following ATI.

ORIGINAL ARTICLES HIV prevention responsibilities in HIV vaccine ...

African Journals Online (AJOL)

HIV/AIDS Vaccines Ethics Group (HAVEG), School of Psychology, University of. KwaZulu-Natal ... receive access to risk reduction counselling on safer sex, education .... debate regarding how to proceed should acyclovir have shown to decrease HIV ... or a single pivotal trial (phase III trial) that provides as much evidence of ...

Predicting hypothetical willingness to participate (WTP) in a future phase III HIV vaccine trial among high-risk adolescents.

Science.gov (United States)

Giocos, Georgina; Kagee, Ashraf; Swartz, Leslie

2008-11-01

The present study sought to determine whether the Theory of Planned Behaviour predicted stated hypothetical willingness to participate (WTP) in future Phase III HIV vaccine trials among South African adolescents. Hierarchical logistic regression analyses showed that The Theory of Planned Behaviour (TPB) significantly predicted WTP. Of all the predictors, Subjective norms significantly predicted WTP (OR = 1.19, 95% C.I. = 1.06-1.34). A stepwise logistic regression analysis revealed that Subjective Norms (OR = 1.19, 95% C.I. = 1.07-1.34) and Attitude towards participation in an HIV vaccine trial (OR = 1.32, 95% C.I. = 1.00-1.74) were significant predictors of WTP. The addition of Knowledge of HIV vaccines and HIV vaccine trials, Perceived self-risk of HIV infection, Health-promoting behaviours and Attitudes towards HIV/AIDS yielded non-significant results. These findings provide support for the Theory of Reasoned Action (TRA) and suggest that psychosocial factors may play an important role in WTP in Phase III HIV vaccine trials among adolescents.

What Has 30 Years of HIV Vaccine Research Taught Us?

Directory of Open Access Journals (Sweden)

José Esparza

2013-10-01

Full Text Available When HIV was discovered and established as the cause of AIDS in 1983–1984, many people believed that a vaccine would be rapidly developed. However, 30 years have passed and we are still struggling to develop an elusive vaccine. In trying to achieve that goal, different scientific paradigms have been explored. Although major progress has been made in understanding the scientific basis for HIV vaccine development, efficacy trials have been critical in moving the field forward. Major lessons learned are: the development of an HIV vaccine is an extremely difficult challenge; the temptation of just following the fashion should be avoided; clinical trials are critical, especially large-scale efficacy trials; HIV vaccine research will require long-term commitment; and sustainable collaborations are needed to accelerate the development of an HIV vaccine. Concrete actions must be implemented with the sense of urgency imposed by the severity of the AIDS epidemic.

Optimization of a multi-gene HIV-1 recombinant subtype CRF02AG DNA vaccine for expression of multiple immunogenic forms

International Nuclear Information System (INIS)

Ellenberger, Dennis; Li Bin; Smith, James; Yi Hong; Folks, Thomas; Robinson, Harriet; Butera, Salvatore

2004-01-01

We developed an AIDS vaccine for Western and West-Central Africa based on a DNA plasmid vector expressing HIV-1 recombinant subtype CRF02 A G gag, pol, and env genes. To optimize the production of noninfectious HIV-like particles (VLPs) and potentially improve the effectiveness of the vaccine, we generated four potential vaccine constructs: the parental (IC2) and three modifications (IC25, IC48, and IC90) containing mutations within the HIV protease. While the parental construct IC2 expressed aggregates of Gag proteins, the IC25 construct resulted in the production of immature VLPs (the core comprises unprocessed Pr 55Gag ). The remaining two constructs (IC48 and IC90) produced mature VLPs (the core comprises processed capsid p24) in addition to immature VLPs and aggregates of Gag proteins. VLPs incorporated significant levels of mature gp120 envelope glycoprotein. Importantly, the mature VLPs were fusion competent and entered coreceptor-specific target cells. The production of multiple antigenic forms, including fusion-competent VLPs, by candidate DNA vaccine constructs may provide immunologic advantages for induction of protective cellular and humoral responses against HIV-1 proteins

HIV/AIDS vaccines for Africa: scientific opportunities, challenges and strategies

Science.gov (United States)

Chin'ombe, Nyasha; Ruhanya, Vurayai

2015-01-01

More than decades have already elapsed since human immunodeficiency virus (HIV) was identified as the causative agent of acquired immunodeficiency syndrome (AIDS). The HIV has since spread to all parts of the world with devastating effects. In sub-saharan Africa, the HIV/AIDS epidemic has reached unprecedented proportions. Safe, effective and affordable HIV/AIDS vaccines for Africans are therefore urgently needed to contain this public health problem. Although, there are challenges, there are also scientific opportunities and strategies that can be exploited in the development of HIV/AIDS vaccines for Africa. The recent RV144 Phase III trial in Thailand has demonstrated that it is possible to develop a vaccine that can potentially elicit modest protective immunity against HIV infection. The main objective of this review is to outline the key scientific opportunities, challenges and strategies in HIV/AIDS vaccine development in Africa. PMID:26185576

Effect of HIV-1 envelope cytoplasmic tail on adenovirus primed virus encoded virus-like particle immunizations

DEFF Research Database (Denmark)

Andersson, Anne Marie C; Ragonnaud, Emeline; Seaton, Kelly E.

2016-01-01

were found between the different priming regimens as both induced high titered tier 1 neutralizing antibodies, but no tier 2 antibodies, possibly reflecting the similar presentation of trimer specific antibody epitopes. The described vaccine regimens provide insight into the effects of the HIV-1 Env......The low number of envelope (Env) spikes presented on native HIV-1 particles is a major impediment for HIV-1 prophylactic vaccine development. We designed virus-like particle encoding adenoviral vectors utilizing SIVmac239 Gag as an anchor for full length and truncated HIV-1 M consensus Env...

Characterization of HIV-1 gp120 antibody specificities induced in anogenital secretions of RV144 vaccine recipients after late boost immunizations.

Directory of Open Access Journals (Sweden)

Siriwat Akapirat

Full Text Available Sexual transmission is the principal driver of the human immunodeficiency virus (HIV pandemic. Understanding HIV vaccine-induced immune responses at mucosal surfaces can generate hypotheses regarding mechanisms of protection, and may influence vaccine development. The RV144 (ClinicalTrials.gov NCT00223080 efficacy trial showed protection against HIV infections but mucosal samples were not collected, therefore, the contribution of mucosal antibodies to preventing HIV-1 acquisition is unknown. Here, we report the generation, magnitude and persistence of antibody responses to recombinant gp120 envelope and antigens including variable one and two loop scaffold antigens (gp70V1V2 previously shown to correlate with risk in RV144. We evaluated antibody responses to gp120 A244gD and gp70V1V2 92TH023 (both CRF01_AE and Case A2 (subtype B in cervico-vaginal mucus (CVM, seminal plasma (SP and rectal secretions (RS from HIV-uninfected RV144 vaccine recipients, who were randomized to receive two late boosts of ALVAC-HIV/AIDSVAX®B/E, AIDSVAX®B/E, or ALVAC-HIV alone at 0 and 6 months. Late vaccine boosting increased IgG geometric mean titers (GMT to gp120 A244gD in AIDSVAX®B/E and ALVAC-HIV/AIDSVAX®B/E CVM (28 and 17 fold, respectively, followed by SP and RS. IgG to gp70V1V2 92TH023 increased in AIDSVAX®B/E and ALVAC-HIV/AIDSVAX®B/E CVM (11-17 fold and SP (2 fold two weeks post first boost. IgG to Case A2 was only detected in AIDSVAX®B/E and ALVAC-HIV/AIDSVAX®B/E CVM. Mucosal IgG to gp120 A244gD (CVM, SP, RS, gp70V1V2 92TH023 (CVM, SP, and Case A2 (CVM correlated with plasma IgG levels (p<0.001. Although the magnitude of IgG responses declined after boosting, anti-gp120 A244gD IgG responses in CVM persisted for 12 months post final vaccination. Further studies in localization, persistence and magnitude of envelope specific antibodies (IgG and dimeric IgA in anogenital secretions will help determine their role in preventing mucosal HIV acquisition.

The Case for Adolescent HIV Vaccination in South Africa: A Cost-Effectiveness Analysis.

Science.gov (United States)

Moodley, Nishila; Gray, Glenda; Bertram, Melanie

2016-01-01

Despite comprising 0.7% of the world population, South Africa is home to 18% of the global human immunodeficiency virus (HIV) prevalence. Unyielding HIV subepidemics among adolescents threaten national attempts to curtail the disease burden. Should an HIV vaccine become available, establishing its point of entry into the health system becomes a priority. This study assesses the impact of school-based HIV vaccination and explores how variations in vaccine characteristics affect cost-effectiveness. The cost per quality adjusted life year (QALY) gained associated with school-based adolescent HIV vaccination services was assessed using Markov modeling that simulated annual cycles based on national costing data. The estimation was based on a life expectancy of 70 years and employs the health care provider perspective. The simultaneous implementation of HIV vaccination services with current HIV management programs would be cost-effective, even at relatively higher vaccine cost. At base vaccine cost of US$ 12, the incremental cost effectiveness ratio (ICER) was US$ 43 per QALY gained, with improved ICER values yielded at lower vaccine costs. The ICER was sensitive to duration of vaccine mediated protection and variations in vaccine efficacy. Data from this work demonstrate that vaccines offering longer duration of protection and at lower cost would result in improved ICER values. School-based HIV vaccine services of adolescents, in addition to current HIV prevention and treatment health services delivered, would be cost-effective.

Importance of neutralization sieve analyses when seeking correlates of HIV-1 vaccine efficacy.

Science.gov (United States)

Montefiori, David C

2014-01-01

This commentary describes a rationale for the use of breakthrough viruses from clinical trial participants to assess neutralizing antibodies as a correlate of HIV-1 vaccine efficacy. The rationale is based on principles of a genetic sieve analysis, where the 2 analyses may be cooperative for delineating neutralizing antibodies as a mechanistic correlate of protection.

Virus-Like-Vaccines against HIV.

Science.gov (United States)

Andersson, Anne-Marie C; Schwerdtfeger, Melanie; Holst, Peter J

2018-02-11

Protection against chronic infections has necessitated the development of ever-more potent vaccination tools. HIV seems to be the most challenging foe, with a remarkable, poorly immunogenic and fragile surface glycoprotein and the ability to overpower the cell immune system. Virus-like-particle (VLP) vaccines have emerged as potent inducers of antibody and helper T cell responses, while replication-deficient viral vectors have yielded potent cytotoxic T cell responses. Here, we review the emerging concept of merging these two technologies into virus-like-vaccines (VLVs) for the targeting of HIV. Such vaccines are immunologically perceived as viruses, as they infect cells and produce VLPs in situ, but they only resemble viruses, as the replication defective vectors and VLPs cannot propagate an infection. The inherent safety of such a platform, despite robust particle production, is a distinct advantage over live-attenuated vaccines that must balance safety and immunogenicity. Previous studies have delivered VLVs encoded in modified Vaccinia Ankara vectors and we have developed the concept into a single-reading adenovirus-based technology capable of eliciting robust CD8⁺ and CD4⁺ T cells responses and trimer binding antibody responses. Such vaccines offer the potential to display the naturally produced immunogen directly and induce an integrated humoral and cellular immune response.

Rational design of HIV vaccine and microbicides: report of the EUROPRISE annual conference.

Science.gov (United States)

Wahren, Britta; Biswas, Priscilla; Borggren, Marie; Coleman, Adam; Da Costa, Kelly; De Haes, Winni; Dieltjens, Tessa; Dispinseri, Stefania; Grupping, Katrijn; Hallengärd, David; Hornig, Julia; Klein, Katja; Mainetti, Lara; Palma, Paolo; Reudelsterz, Marc; Seifried, Janna; Selhorst, Philippe; Sköld, Annette; Uchtenhagen, Hannes; van Gils, Marit J; Weber, Caroline; Shattock, Robin; Scarlatti, Gabriella

2010-07-26

EUROPRISE is a Network of Excellence sponsored from 2007 to 2011 by the European Commission within the 6th Framework Program. The Network encompasses a wide portfolio of activities ranging from an integrated research program in the field of HIV vaccines and microbicides to training, dissemination and advocacy. The research program covers the whole pipeline of vaccine and microbicide development from discovery to early clinical trials. The Network is composed of 58 partners representing more than 65 institutions from 13 European countries; it also includes three major pharmaceutical companies (GlaxoSmithKline, Novartis and Sanofi-Pasteur) involved in HIV microbicide and vaccine research. The Network displays a dedicated and informative web page: http://www.europrise.org. Finally, a distinguishing trait of EUROPRISE is its PhD School of students from across Europe, a unique example in the world of science aimed at spreading excellence through training. EUROPRISE held its second annual conference in Budapest in November, 2009. The conference had 143 participants and their presentations covered aspects of vaccine and microbicide research, development and discovery. Since training is a major task of the Network, the students of the EUROPRISE PhD program summarized certain presentations and their view of the conference in this paper.

Rational design of HIV vaccine and microbicides: report of the EUROPRISE annual conference

Directory of Open Access Journals (Sweden)

Mainetti Lara

2010-07-01

Full Text Available Abstract EUROPRISE is a Network of Excellence sponsored from 2007 to 2011 by the European Commission within the 6th Framework Program. The Network encompasses a wide portfolio of activities ranging from an integrated research program in the field of HIV vaccines and microbicides to training, dissemination and advocacy. The research program covers the whole pipeline of vaccine and microbicide development from discovery to early clinical trials. The Network is composed of 58 partners representing more than 65 institutions from 13 European countries; it also includes three major pharmaceutical companies (GlaxoSmithKline, Novartis and Sanofi-Pasteur involved in HIV microbicide and vaccine research. The Network displays a dedicated and informative web page: http://www.europrise.org. Finally, a distinguishing trait of EUROPRISE is its PhD School of students from across Europe, a unique example in the world of science aimed at spreading excellence through training. EUROPRISE held its second annual conference in Budapest in November, 2009. The conference had 143 participants and their presentations covered aspects of vaccine and microbicide research, development and discovery. Since training is a major task of the Network, the students of the EUROPRISE PhD program summarized certain presentations and their view of the conference in this paper.

Preliminary Report on HIV-1 Vaccine Preparedness in Nigeria: Advantages of Recruiting University Students

Directory of Open Access Journals (Sweden)

Ruth Guyit

2010-01-01

Full Text Available The national HIV seroprevalence in Nigeria has risen steeply from about 3% in 1993 to 5-8% in 2001 and now stands at 4.4%. HIV epidemic continues to be a serious threat to the most populous country in Africa with a population of 140 million, with limited use of antiviral drugs that is taken for life since it only suppresses the virus without completely eliminating the virus or leading to cure. Only a change in social behavior and an affordable vaccine can halt the epidemic in Africa. We report here results of a pilot study on the recruitment strategies, sociodemographic aspects and HIV risk behavior of a cohort of normal volunteers recruited at the University of Jos, Nigeria. Our study recorded a high degree of interest and zeal to participate in HIV vaccine studies by volunteers, and demonstrated the superiority of snowballing over invitation by mail, as a recruitment strategy. A cohort of university students may be particularly suitable for conducting HIV vaccine trials because of the assurance of prospective follow-up for up to four years (time to graduation, and a good understanding of the risks and benefits of participation as outlined in the informed consent. We had 100% retention during a follow-up period of two years. Most importantly, the cohort reflected a relatively low HIV seroprevalence, which gives preventive programs the potential to blunt or halt the epidemic.

[Vaccine for human immunodeficiency virus (HIV)--relevance of these days].

Science.gov (United States)

Laiskonis, Alvydas; Pukenyte, Evelina

2005-01-01

Since 1980 more than 25 million people have died from acquired immunodeficiency syndrome (AIDS), which results from infection with human immunodeficiency virus (HIV). Number of new cases increases very threateningly. One and the most effective method to stop the progress of epidemic is the development of the vaccine for HIV. There is the presentation of the first stage of the vaccine for HIV testing (structure, methodology), which is now on trial in St. Pierre hospital, Brussels University. HIV characteristics which inflame the process of the vaccine development, historical facts and facts about vaccines on trial in these days are reviewed in this article. More than 10,000 volunteers have been participating in various clinical trials since 1987. The development of the vaccine is a very difficult, long-terming (about 8-10 years) and costly process. The process of the vaccine testing is very difficult in developing countries where the infection spreads the most rapidly. Available data confirm that the vaccine must be multi-componential, inducing cellular, humoral immunity against various subtypes of HIV. The vaccine cannot protect fully but the changes of the natural infection course could decrease virulence, distance the stage of AIDS, and retard the spread of the epidemic.

Evolving T-cell vaccine strategies for HIV, the virus with a thousand faces

Energy Technology Data Exchange (ETDEWEB)

Korber, Bette [Los Alamos National Laboratory

2009-01-01

HIV's rapid global spread and the human suffering it has left in its wake have made AIDS a global heath priority for the 25 years since its discovery. Yet its capacity to rapidly evolve has made combating this virus a tremendous challenge. The obstacles to creating an effective HIV vaccine are formidable, but there are advances in the field on many fronts, in terms of novel vectors, adjuvants, and antigen design strategies. SIV live attenuated vaccine models are able to confer protection against heterologous challenge, and this continues to provide opportunities to explore the biological underpinnings of a protective effect (9). More indirect, but equally important, is new understanding regarding the biology of acute infection (43), the role of immune response in long-term non-progression (6,62, 81), and defining characteristics of broadly neutralizing antibodies (4). In this review we will focus on summarizing strategies directed towards a single issue, that of contending with HIV variation in terms of designing aT-cell vaccine. The strategies that prove most effective in this area can ultimately be combined with the best strategies under development in other areas, with the hope of ultimately converging on a viable vaccine candidate. Only two large HIV vaccine efficacy trials have been completed and both have failed to prevent infection or confer a benefit to infected individual (23,34), but there is ample reason to continue our efforts. A historic breakthrough came in 1996, when it was realized that although the virus could escape from a single antiretroviral (ARV) therapy, it could be thwarted by a combination of medications that simultaneously targeted different parts of the virus (HAART) (38). This revelation came after 15 years of research, thought, and clinical testing; to enable that vital progress the research and clinical communities had to first define and understand, then develop a strategy to counter, the remarkable evolutionary potential of the

Organizing the HIV vaccine development effort.

Science.gov (United States)

Voronin, Yegor; Snow, William

2013-09-01

To describe and compare the diverse organizational structures and funding mechanisms applied to advance HIV preventive vaccine research and development and to help explain and inform evolving infrastructures and collaborative funding models. On the basis of models that have been tried, improved or abandoned over three decades, the field seems to have settled into a relatively stable set of diverse initiatives, each with its own organizational signature. At the same time, this set of organizations is forging cross-organizational collaborations, which promise to acquire newly emergent beneficial properties. Strong motivation to expedite HIV vaccine R&D has driven a diversity of customized and inventive organizational approaches, largely government and foundation funded. Although no one approach has proven a panacea, the field has evolved into a constellation of often overlapping organizations that complement or reinforce one another. The Global HIV Vaccine Enterprise, a responsive, rapidly evolving loose infrastructure, is an innovative collaboration to catalyze that evolution.

Patent data mining: a tool for accelerating HIV vaccine innovation.

Science.gov (United States)

Clark, K; Cavicchi, J; Jensen, K; Fitzgerald, R; Bennett, A; Kowalski, S P

2011-05-31

Global access to advanced vaccine technologies is challenged by the interrelated components of intellectual property (IP) management strategies, technology transfer (legal and technical) capabilities and the capacity necessary for accelerating R&D, commercialization and delivery of vaccines. Due to a negative association with the management of IP, patents are often overlooked as a vast resource of freely available, information akin to scientific journals as well as business and technological information and trends fundamental for formulating policies and IP management strategies. Therefore, a fundamental step towards facilitating global vaccine access will be the assembly, organization and analysis of patent landscapes, to identify the amount of patenting, ownership (assignees) and fields of technology covered. This is critical for making informed decisions (e.g., identifying licensees, building research and product development collaborations, and ascertaining freedom to operate). Such information is of particular interest to the HIV vaccine community where the HIV Vaccine Enterprise, have voiced concern that IP rights (particularly patents and trade secrets) may prevent data and materials sharing, delaying progress in research and development of a HIV vaccine. We have compiled and analyzed a representative HIV vaccine patent landscape for a prime-boost, DNA/adenoviral vaccine platform, as an example for identifying obstacles, maximizing opportunities and making informed IP management strategy decisions towards the development and deployment of an efficacious HIV vaccine. Copyright © 2011 Elsevier Ltd. All rights reserved.

Generation and Characterization of a Defective HIV-1 Virus as an Immunogen for a Therapeutic Vaccine

Science.gov (United States)

García-Pérez, Javier; García, Felipe; Blanco, Julia; Escribà-García, Laura; Gatell, Jose Maria; Alcamí, Jose; Plana, Montserrat; Sánchez-Palomino, Sonsoles

2012-01-01

Background The generation of new immunogens able to elicit strong specific immune responses remains a major challenge in the attempts to obtain a prophylactic or therapeutic vaccine against HIV/AIDS. We designed and constructed a defective recombinant virus based on the HIV-1 genome generating infective but non-replicative virions able to elicit broad and strong cellular immune responses in HIV-1 seropositive individuals. Results Viral particles were generated through transient transfection in producer cells (293-T) of a full length HIV-1 DNA carrying a deletion of 892 base pairs (bp) in the pol gene encompassing the sequence that codes for the reverse transcriptase (NL4-3/ΔRT clone). The viral particles generated were able to enter target cells, but due to the absence of reverse transcriptase no replication was detected. The immunogenic capacity of these particles was assessed by ELISPOT to determine γ-interferon production in a cohort of 69 chronic asymptomatic HIV-1 seropositive individuals. Surprisingly, defective particles produced from NL4-3/ΔRT triggered stronger cellular responses than wild-type HIV-1 viruses inactivated with Aldrithiol-2 (AT-2) and in a larger proportion of individuals (55% versus 23% seropositive individuals tested). Electron microscopy showed that NL4-3/ΔRT virions display immature morphology. Interestingly, wild-type viruses treated with Amprenavir (APV) to induce defective core maturation also induced stronger responses than the same viral particles generated in the absence of protease inhibitors. Conclusions We propose that immature HIV-1 virions generated from NL4-3/ΔRT viral clones may represent new prototypes of immunogens with a safer profile and stronger capacity to induce cellular immune responses than wild-type inactivated viral particles. PMID:23144996

The F4/AS01B HIV-1 Vaccine Candidate Is Safe and Immunogenic, But Does Not Show Viral Efficacy in Antiretroviral Therapy-Naive, HIV-1-Infected Adults

Science.gov (United States)

Dinges, Warren; Girard, Pierre-Marie; Podzamczer, Daniel; Brockmeyer, Norbert H.; García, Felipe.; Harrer, Thomas; Lelievre, Jean-Daniel; Frank, Ian; Colin De Verdière, Nathalie; Yeni, Guy-Patrick; Ortega Gonzalez, Enrique; Rubio, Rafael; Clotet Sala, Bonaventura; DeJesus, Edwin; Pérez-Elias, Maria Jesus; Launay, Odile; Pialoux, Gilles; Slim, Jihad; Weiss, Laurence; Bouchaud, Olivier; Felizarta, Franco; Meurer, Anja; Raffi, François; Esser, Stefan; Katlama, Christine; Koletar, Susan L.; Mounzer, Karam; Swindells, Susan; Baxter, John D.; Schneider, Stefan; Chas, Julie; Molina, Jean-Michel; Koutsoukos, Marguerite; Collard, Alix; Bourguignon, Patricia; Roman, François

2016-01-01

Abstract The impact of the investigational human immunodeficiency virus type 1 (HIV-1) F4/AS01B vaccine on HIV-1 viral load (VL) was evaluated in antiretroviral therapy (ART)-naive HIV-1 infected adults. This phase IIb, observer-blind study (NCT01218113), included ART-naive HIV-1 infected adults aged 18 to 55 years. Participants were randomized to receive 2 (F4/AS01B_2 group, N = 64) or 3 (F4/AS01B_3 group, N = 62) doses of F4/AS01B or placebo (control group, N = 64) at weeks 0, 4, and 28. Efficacy (HIV-1 VL, CD4+ T-cell count, ART initiation, and HIV-related clinical events), safety, and immunogenicity (antibody and T-cell responses) were evaluated during 48 weeks. At week 48, based on a mixed model, no statistically significant difference in HIV-1 VL change from baseline was demonstrated between F4/AS01B_2 and control group (0.073 log10 copies/mL [97.5% confidence interval (CI): −0.088; 0.235]), or F4/AS01B_3 and control group (−0.096 log10 copies/mL [97.5% CI: −0.257; 0.065]). No differences between groups were observed in HIV-1 VL change, CD4+ T-cell count, ART initiation, or HIV-related clinical events at intermediate timepoints. Among F4/AS01B recipients, the most frequent solicited symptoms were pain at injection site (252/300 doses), fatigue (137/300 doses), myalgia (105/300 doses), and headache (90/300 doses). Twelve serious adverse events were reported in 6 participants; 1 was considered vaccine-related (F4/AS01B_2 group: angioedema). F4/AS01B induced polyfunctional F4-specific CD4+ T-cells, but had no significant impact on F4-specific CD8+ T-cell and anti-F4 antibody levels. F4/AS01B had a clinically acceptable safety profile, induced F4-specific CD4+ T-cell responses, but did not reduce HIV-1 VL, impact CD4+ T-cells count, delay ART initiation, or prevent HIV-1 related clinical events. PMID:26871794

Simultaneous approach using systemic, mucosal and transcutaneous routes of immunization for development of protective HIV-1 vaccines.

Science.gov (United States)

Belyakov, I M; Ahlers, J D

2011-01-01

Mucosal tissues are major sites of HIV entry and initial infection. Induction of a local mucosal cytotoxic T lymphocyte response is considered an important goal in developing an effective HIV vaccine. In addition, activation and recruitment of memory CD4(+) and CD8(+) T cells in systemic lymphoid circulation to mucosal effector sites might provide the firewall needed to prevent virus spread. Therefore a vaccine that generates CD4(+) and CD8(+) responses in both mucosal and systemic tissues might be required for protection against HIV. However, optimal routes and number of vaccinations required for the generation of long lasting CD4(+) and CD8(+) CTL effector and memory responses are not well understood especially for mucosal T cells. A number of studies looking at protective immune responses against diverse mucosal pathogens have shown that mucosal vaccination is necessary to induce a compartmentalized immune response including maximum levels of mucosal high-avidity CD8(+) CTL, antigen specific mucosal antibodies titers (especially sIgA), as well as induction of innate anti-viral factors in mucosa tissue. Immune responses are detectable at mucosal sites after systemic delivery of vaccine, and prime boost regimens can amplify the magnitude of immune responses in mucosal sites and in systemic lymphoid tissues. We believe that the most optimal mucosal and systemic HIV/SIV specific protective immune responses and innate factors might best be achieved by simultaneous mucosal and systemic prime and boost vaccinations. Similar principals of vaccination may be applied for vaccine development against cancer and highly invasive pathogens that lead to chronic infection.

Adolescent decision making about participation in a hypothetical HIV vaccine trial.

Science.gov (United States)

Alexander, Andreia B; Ott, Mary A; Lally, Michelle A; Sniecinski, Kevin; Baker, Alyne; Zimet, Gregory D

2015-03-10

The purpose of this study was to examine the process of adolescent decision-making about participation in an HIV vaccine clinical trial, comparing it to adult models of informed consent with attention to developmental differences. As part of a larger study of preventive misconception in adolescent HIV vaccine trials, we interviewed 33 male and female 16-19-year-olds who have sex with men. Participants underwent a simulated HIV vaccine trial consent process, and then completed a semistructured interview about their decision making process when deciding whether or not to enroll in and HIV vaccine trial. An ethnographic content analysis approach was utilized. Twelve concepts related to adolescents' decision-making about participation in an HIV vaccine trial were identified and mapped onto Appelbaum and Grisso's four components of decision making capacity including understanding of vaccines and how they work, the purpose of the study, trial procedures, and perceived trial risks and benefits, an appreciation of their own situation, the discussion and weighing of risks and benefits, discussing the need to consult with others about participation, motivations for participation, and their choice to participate. The results of this study suggest that most adolescents at high risk for HIV demonstrate the key abilities needed to make meaningful decisions about HIV vaccine clinical trial participation. Published by Elsevier Ltd.

Subtype C gp140 Vaccine Boosts Immune Responses Primed by the South African AIDS Vaccine Initiative DNA-C2 and MVA-C HIV Vaccines after More than a 2-Year Gap.

Science.gov (United States)

Gray, Glenda E; Mayer, Kenneth H; Elizaga, Marnie L; Bekker, Linda-Gail; Allen, Mary; Morris, Lynn; Montefiori, David; De Rosa, Stephen C; Sato, Alicia; Gu, Niya; Tomaras, Georgia D; Tucker, Timothy; Barnett, Susan W; Mkhize, Nonhlanhla N; Shen, Xiaoying; Downing, Katrina; Williamson, Carolyn; Pensiero, Michael; Corey, Lawrence; Williamson, Anna-Lise

2016-06-01

A phase I safety and immunogenicity study investigated South African AIDS Vaccine Initiative (SAAVI) HIV-1 subtype C (HIV-1C) DNA vaccine encoding Gag-RT-Tat-Nef and gp150, boosted with modified vaccinia Ankara (MVA) expressing matched antigens. Following the finding of partial protective efficacy in the RV144 HIV vaccine efficacy trial, a protein boost with HIV-1 subtype C V2-deleted gp140 with MF59 was added to the regimen. A total of 48 participants (12 U.S. participants and 36 Republic of South Africa [RSA] participants) were randomized to receive 3 intramuscular (i.m.) doses of SAAVI DNA-C2 of 4 mg (months 0, 1, and 2) and 2 i.m. doses of SAAVI MVA-C of 1.45 × 10(9) PFU (months 4 and 5) (n = 40) or of a placebo (n = 8). Approximately 2 years after vaccination, 27 participants were rerandomized to receive gp140/MF59 at 100 μg or placebo, as 2 i.m. injections, 3 months apart. The vaccine regimen was safe and well tolerated. After the DNA-MVA regimen, CD4(+) T-cell and CD8(+) T-cell responses occurred in 74% and 32% of the participants, respectively. The protein boost increased CD4(+) T-cell responses to 87% of the subjects. All participants developed tier 1 HIV-1C neutralizing antibody responses as well as durable Env binding antibodies that recognized linear V3 and C5 peptides. The HIV-1 subtype C DNA-MVA vaccine regimen showed promising cellular immunogenicity. Boosting with gp140/MF59 enhanced levels of binding and neutralizing antibodies as well as CD4(+) T-cell responses to HIV-1 envelope. (This study has been registered at ClinicalTrials.gov under registration no. NCT00574600 and NCT01423825.). Copyright © 2016 Gray et al.

Rational design of HIV vaccines and microbicides: report of the EUROPRISE network annual conference 2010

Directory of Open Access Journals (Sweden)

Uchtenhagen Hannes

2011-04-01

Full Text Available Abstract Novel, exciting intervention strategies to prevent infection with HIV have been tested in the past year, and the field is rapidly evolving. EUROPRISE is a network of excellence sponsored by the European Commission and concerned with a wide range of activities including integrated developmental research on HIV vaccines and microbicides from discovery to early clinical trials. A central and timely theme of the network is the development of the unique concept of co-usage of vaccines and microbicides. This review, prepared by the PhD students of the network captures much of the research ongoing between the partners. The network is in its 5th year and involves over 50 institutions from 13 European countries together with 3 industrial partners; GSK, Novartis and Sanofi-Pasteur. EUROPRISE is involved in 31 separate world-wide trials of Vaccines and Microbicides including 6 in African countries (Tanzania, Mozambique, South Africa, Kenya, Malawi, Rwanda, and is directly supporting clinical trials including MABGEL, a gp140-hsp70 conjugate trial and HIVIS, vaccine trials in Europe and Africa.

Rational design of HIV vaccines and microbicides: report of the EUROPRISE network annual conference 2010.

Science.gov (United States)

Brinckmann, Sarah; da Costa, Kelly; van Gils, Marit J; Hallengärd, David; Klein, Katja; Madeira, Luisa; Mainetti, Lara; Palma, Paolo; Raue, Katharina; Reinhart, David; Reudelsterz, Marc; Ruffin, Nicolas; Seifried, Janna; Schäfer, Katrein; Sheik-Khalil, Enas; Sköld, Annette; Uchtenhagen, Hannes; Vabret, Nicolas; Ziglio, Serena; Scarlatti, Gabriella; Shattock, Robin; Wahren, Britta; Gotch, Frances

2011-04-12

Novel, exciting intervention strategies to prevent infection with HIV have been tested in the past year, and the field is rapidly evolving. EUROPRISE is a network of excellence sponsored by the European Commission and concerned with a wide range of activities including integrated developmental research on HIV vaccines and microbicides from discovery to early clinical trials. A central and timely theme of the network is the development of the unique concept of co-usage of vaccines and microbicides. This review, prepared by the PhD students of the network captures much of the research ongoing between the partners. The network is in its 5th year and involves over 50 institutions from 13 European countries together with 3 industrial partners; GSK, Novartis and Sanofi-Pasteur. EUROPRISE is involved in 31 separate world-wide trials of Vaccines and Microbicides including 6 in African countries (Tanzania, Mozambique, South Africa, Kenya, Malawi, Rwanda), and is directly supporting clinical trials including MABGEL, a gp140-hsp70 conjugate trial and HIVIS, vaccine trials in Europe and Africa.

Resolving legal, ethical, and human rights challenges in HIV vaccine research.

Science.gov (United States)

Patterson, D

2000-01-01

In the absence of a cure for AIDS, attention has turned to the possibility of developing a preventive vaccine for HIV infection. Yet many scientific, ethical, legal, and economic obstacles remain. At the current rate, the development and production of an effective vaccine could take 15 to 20 years or longer. If tens of millions more HIV infections and deaths are to be avoided in the coming decades, vaccine research needs to be greatly expedited. Furthermore, it must be undertaken ethically, and the products of this research must benefit people in developing countries. This article, an edited and updated version of a paper presented at "Putting Third First," addresses challenges arising in HIV preventive vaccine research in developing countries. It does not address clinical research in developing countries relating to treatments or therapeutic vaccines. Nor does it address legal and ethical issues relating to HIV vaccine research in industrialized countries, although similar issues arise in both contexts. The article concludes that while ethical codes are silent on the obligation to undertake research and development, international law provides strong legal obligations--particularly with regard to industrialized states--that should be invoked to accelerate HIV vaccine development, and distribution.

Adherence to hepatitis A virus vaccination in HIV-infected men who have sex with men.

Science.gov (United States)

Kourkounti, Sofia; Paparizos, Vassilios; Leuow, Kirsten; Paparizou, Eleni; Antoniou, Christina

2015-10-01

Although vaccination against hepatitis A virus (HAV) is essential for human immunodeficiency virus (HIV)-infected patients, the uptake of HAV vaccine is reported to be very low. From 2007 to 2012, 912 HIV-infected men in Athens, Greece were screened for exposure to HAV. Two doses of an HAV vaccine were recommended to 569 eligible patients. Reminder cards with scheduled vaccination visits were given to each patient. Among eligible patients, 62.2% (354/569) received both doses. Patients who were fully vaccinated compared with non-adherent patients were natives, older, had undetectable HIV viral load, higher CD4 T cell counts and lower nadir CD4 T cell counts. Multivariate logistic regression revealed that the patient's country of origin (p = 0.024; OR = 2.712; 95% CI, 1.139-6.457), CD4 T cell count (p < 0.001) and nadir CD4 T cell count (p < 0.001) were factors directly associated with adherence. In conclusion, adherence to HAV vaccination was better than in previously published data. Because many of the factors related to vaccination completion are parameters of HIV infection, it appears that physician interest in HIV care and vaccination planning is crucial to enhancing vaccine uptake. © The Author(s) 2015.

Optimization of HIV-1 Envelope DNA Vaccine Candidates within Three Different Animal Models, Guinea Pigs, Rabbits and Cynomolgus Macaques.

Science.gov (United States)

Borggren, Marie; Vinner, Lasse; Andresen, Betina Skovgaard; Grevstad, Berit; Repits, Johanna; Melchers, Mark; Elvang, Tara Laura; Sanders, Rogier W; Martinon, Frédéric; Dereuddre-Bosquet, Nathalie; Bowles, Emma Joanne; Stewart-Jones, Guillaume; Biswas, Priscilla; Scarlatti, Gabriella; Jansson, Marianne; Heyndrickx, Leo; Grand, Roger Le; Fomsgaard, Anders

2013-07-19

HIV-1 DNA vaccines have many advantageous features. Evaluation of HIV-1 vaccine candidates often starts in small animal models before macaque and human trials. Here, we selected and optimized DNA vaccine candidates through systematic testing in rabbits for the induction of broadly neutralizing antibodies (bNAb). We compared three different animal models: guinea pigs, rabbits and cynomolgus macaques. Envelope genes from the prototype isolate HIV-1 Bx08 and two elite neutralizers were included. Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed. Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity. Evaluations of rabbits and guinea pigs displayed similar results. The superior DNA construct in rabbits was a trivalent mix of non-modified codon-optimized gp140 envelope genes. Despite NAb responses with some potency and breadth in guinea pigs and rabbits, the DNA vaccinated macaques displayed less bNAb activity. It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.

Optimization of HIV-1 Envelope DNA Vaccine Candidates within Three Different Animal Models, Guinea Pigs, Rabbits and Cynomolgus Macaques

Directory of Open Access Journals (Sweden)

Roger Le Grand

2013-07-01

Full Text Available HIV-1 DNA vaccines have many advantageous features. Evaluation of HIV-1 vaccine candidates often starts in small animal models before macaque and human trials. Here, we selected and optimized DNA vaccine candidates through systematic testing in rabbits for the induction of broadly neutralizing antibodies (bNAb. We compared three different animal models: guinea pigs, rabbits and cynomolgus macaques. Envelope genes from the prototype isolate HIV-1 Bx08 and two elite neutralizers were included. Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed. Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity. Evaluations of rabbits and guinea pigs displayed similar results. The superior DNA construct in rabbits was a trivalent mix of non-modified codon-optimized gp140 envelope genes. Despite NAb responses with some potency and breadth in guinea pigs and rabbits, the DNA vaccinated macaques displayed less bNAb activity. It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.

CD4/CD8 Ratio and KT Ratio Predict Yellow Fever Vaccine Immunogenicity in HIV-Infected Patients.

Science.gov (United States)

Avelino-Silva, Vivian I; Miyaji, Karina T; Hunt, Peter W; Huang, Yong; Simoes, Marisol; Lima, Sheila B; Freire, Marcos S; Caiaffa-Filho, Helio H; Hong, Marisa A; Costa, Dayane Alves; Dias, Juliana Zanatta C; Cerqueira, Natalia B; Nishiya, Anna Shoko; Sabino, Ester Cerdeira; Sartori, Ana M; Kallas, Esper G

2016-12-01

HIV-infected individuals have deficient responses to Yellow Fever vaccine (YFV) and may be at higher risk for adverse events (AE). Chronic immune activation-characterized by low CD4/CD8 ratio or high indoleamine 2,3-dioxygenase-1 (IDO) activity-may influence vaccine response in this population. We prospectively assessed AE, viremia by the YFV virus and YF-specific neutralizing antibodies (NAb) in HIV-infected (CD4>350) and -uninfected adults through 1 year after vaccination. The effect of HIV status on initial antibody response to YFV was measured during the first 3 months following vaccination, while the effect on persistence of antibody response was measured one year following vaccination. We explored CD4/CD8 ratio, IDO activity (plasma kynurenine/tryptophan [KT] ratio) and viremia by Human Pegivirus as potential predictors of NAb response to YFV among HIV-infected participants with linear mixed models. 12 HIV-infected and 45-uninfected participants were included in the final analysis. HIV was not significantly associated with AE, YFV viremia or NAb titers through the first 3 months following vaccination. However, HIV-infected participants had 0.32 times the NAb titers observed for HIV-uninfected participants at 1 year following YFV (95% CI 0.13 to 0.83, p = 0.021), independent of sex, age and prior vaccination. In HIV-infected participants, each 10% increase in CD4/CD8 ratio predicted a mean 21% higher post-baseline YFV Nab titer (p = 0.024). Similarly, each 10% increase in KT ratio predicted a mean 21% lower post-baseline YFV Nab titer (p = 0.009). Viremia by Human Pegivirus was not significantly associated with NAb titers. HIV infection appears to decrease the durability of NAb responses to YFV, an effect that may be predicted by lower CD4/CD8 ratio or higher KT ratio.

Rational design of HIV vaccine and microbicides: report of the EUROPRISE annual conference

NARCIS (Netherlands)

Wahren, Britta; Biswas, Priscilla; Borggren, Marie; Coleman, Adam; Da Costa, Kelly; de Haes, Winni; Dieltjens, Tessa; Dispinseri, Stefania; Grupping, Katrijn; Hallengärd, David; Hornig, Julia; Klein, Katja; Mainetti, Lara; Palma, Paolo; Reudelsterz, Marc; Seifried, Janna; Selhorst, Philippe; Sköld, Annette; Uchtenhagen, Hannes; van Gils, Marit J.; Weber, Caroline; Shattock, Robin; Scarlatti, Gabriella

2010-01-01

EUROPRISE is a Network of Excellence sponsored from 2007 to 2011 by the European Commission within the 6th Framework Program. The Network encompasses a wide portfolio of activities ranging from an integrated research program in the field of HIV vaccines and microbicides to training, dissemination

Phase I safety and immunogenicity evaluation of MVA-CMDR, a multigenic, recombinant modified vaccinia Ankara-HIV-1 vaccine candidate.

Science.gov (United States)

Currier, Jeffrey R; Ngauy, Viseth; de Souza, Mark S; Ratto-Kim, Silvia; Cox, Josephine H; Polonis, Victoria R; Earl, Patricia; Moss, Bernard; Peel, Sheila; Slike, Bonnie; Sriplienchan, Somchai; Thongcharoen, Prasert; Paris, Robert M; Robb, Merlin L; Kim, Jerome; Michael, Nelson L; Marovich, Mary A

2010-11-15

We conducted a Phase I randomized, dose-escalation, route-comparison trial of MVA-CMDR, a candidate HIV-1 vaccine based on a recombinant modified vaccinia Ankara viral vector expressing HIV-1 genes env/gag/pol. The HIV sequences were derived from circulating recombinant form CRF01_AE, which predominates in Thailand. The objective was to evaluate safety and immunogenicity of MVA-CMDR in human volunteers in the US and Thailand. MVA-CMDR or placebo was administered intra-muscularly (IM; 10(7) or 10(8) pfu) or intradermally (ID; 10(6) or 10(7) pfu) at months 0, 1 and 3, to 48 healthy volunteers at low risk for HIV-1 infection. Twelve volunteers in each dosage group were randomized to receive MVA-CMDR or placebo (10∶2). Volunteers were actively monitored for local and systemic reactogenicity and adverse events post vaccination. Cellular immunogenicity was assessed by a validated IFNγ Elispot assay, an intracellular cytokine staining assay, lymphocyte proliferation and a (51)Cr-release assay. Humoral immunogenicity was assessed by ADCC for gp120 and binding antibody ELISAs for gp120 and p24. MVA-CMDR was safe and well tolerated with no vaccine related serious adverse events. Cell-mediated immune responses were: (i) moderate in magnitude (median IFNγ Elispot of 78 SFC/10(6) PBMC at 10(8) pfu IM), but high in response rate (70% (51)Cr-release positive; 90% Elispot positive; 100% ICS positive, at 10(8) pfu IM); (ii) predominantly HIV Env-specific CD4(+) T cells, with a high proliferative capacity and durable for at least 6 months (100% LPA response rate by the IM route); (iv) dose- and route-dependent with 10(8) pfu IM being the most immunogenic treatment. Binding antibodies against gp120 and p24 were detectable in all vaccination groups with ADCC capacity detectable at the highest dose (40% positive at 10(8) pfu IM). MVA-CMDR delivered both intramuscularly and intradermally was safe, well-tolerated and elicited durable cell-mediated and humoral immune responses

Phase I safety and immunogenicity evaluation of MVA-CMDR, a multigenic, recombinant modified vaccinia Ankara-HIV-1 vaccine candidate.

Directory of Open Access Journals (Sweden)

Jeffrey R Currier

2010-11-01

Full Text Available We conducted a Phase I randomized, dose-escalation, route-comparison trial of MVA-CMDR, a candidate HIV-1 vaccine based on a recombinant modified vaccinia Ankara viral vector expressing HIV-1 genes env/gag/pol. The HIV sequences were derived from circulating recombinant form CRF01_AE, which predominates in Thailand. The objective was to evaluate safety and immunogenicity of MVA-CMDR in human volunteers in the US and Thailand.MVA-CMDR or placebo was administered intra-muscularly (IM; 10(7 or 10(8 pfu or intradermally (ID; 10(6 or 10(7 pfu at months 0, 1 and 3, to 48 healthy volunteers at low risk for HIV-1 infection. Twelve volunteers in each dosage group were randomized to receive MVA-CMDR or placebo (10∶2. Volunteers were actively monitored for local and systemic reactogenicity and adverse events post vaccination. Cellular immunogenicity was assessed by a validated IFNγ Elispot assay, an intracellular cytokine staining assay, lymphocyte proliferation and a (51Cr-release assay. Humoral immunogenicity was assessed by ADCC for gp120 and binding antibody ELISAs for gp120 and p24. MVA-CMDR was safe and well tolerated with no vaccine related serious adverse events. Cell-mediated immune responses were: (i moderate in magnitude (median IFNγ Elispot of 78 SFC/10(6 PBMC at 10(8 pfu IM, but high in response rate (70% (51Cr-release positive; 90% Elispot positive; 100% ICS positive, at 10(8 pfu IM; (ii predominantly HIV Env-specific CD4(+ T cells, with a high proliferative capacity and durable for at least 6 months (100% LPA response rate by the IM route; (iv dose- and route-dependent with 10(8 pfu IM being the most immunogenic treatment. Binding antibodies against gp120 and p24 were detectable in all vaccination groups with ADCC capacity detectable at the highest dose (40% positive at 10(8 pfu IM.MVA-CMDR delivered both intramuscularly and intradermally was safe, well-tolerated and elicited durable cell-mediated and humoral immune responses

CD4/CD8 Ratio and KT Ratio Predict Yellow Fever Vaccine Immunogenicity in HIV-Infected Patients

Science.gov (United States)

Hunt, Peter W.; Huang, Yong; Simoes, Marisol; Lima, Sheila B.; Freire, Marcos S.; Caiaffa-Filho, Helio H.; Hong, Marisa A.; Costa, Dayane Alves; Dias, Juliana Zanatta C.; Cerqueira, Natalia B.; Nishiya, Anna Shoko; Sabino, Ester Cerdeira; Sartori, Ana M.; Kallas, Esper G.

2016-01-01

Background HIV-infected individuals have deficient responses to Yellow Fever vaccine (YFV) and may be at higher risk for adverse events (AE). Chronic immune activation–characterized by low CD4/CD8 ratio or high indoleamine 2,3-dioxygenase-1 (IDO) activity—may influence vaccine response in this population. Methods We prospectively assessed AE, viremia by the YFV virus and YF-specific neutralizing antibodies (NAb) in HIV-infected (CD4>350) and -uninfected adults through 1 year after vaccination. The effect of HIV status on initial antibody response to YFV was measured during the first 3 months following vaccination, while the effect on persistence of antibody response was measured one year following vaccination. We explored CD4/CD8 ratio, IDO activity (plasma kynurenine/tryptophan [KT] ratio) and viremia by Human Pegivirus as potential predictors of NAb response to YFV among HIV-infected participants with linear mixed models. Results 12 HIV-infected and 45-uninfected participants were included in the final analysis. HIV was not significantly associated with AE, YFV viremia or NAb titers through the first 3 months following vaccination. However, HIV–infected participants had 0.32 times the NAb titers observed for HIV-uninfected participants at 1 year following YFV (95% CI 0.13 to 0.83, p = 0.021), independent of sex, age and prior vaccination. In HIV-infected participants, each 10% increase in CD4/CD8 ratio predicted a mean 21% higher post-baseline YFV Nab titer (p = 0.024). Similarly, each 10% increase in KT ratio predicted a mean 21% lower post-baseline YFV Nab titer (p = 0.009). Viremia by Human Pegivirus was not significantly associated with NAb titers. Conclusions HIV infection appears to decrease the durability of NAb responses to YFV, an effect that may be predicted by lower CD4/CD8 ratio or higher KT ratio. PMID:27941965

Community perspectives on the ethical issues surrounding adolescent HIV vaccine trials in South Africa.

Science.gov (United States)

Jaspan, Heather B; Soka, Nosiphiwo F; Strode, Ann E; Mathews, Catherine; Mark, Daniella; Flisher, Alan J; Wood, Robin; Bekker, Linda-Gail

2008-10-23

Adolescents globally are at high risk for HIV acquisition and are the targets of HIV prevention interventions such as HIV vaccines. In order to understand stakeholders' attitudes towards the ethical issues of adolescent involvement in HIV vaccine trials, we conducted focus group discussions with key members of a semi-urban, informal Cape Town community with high HIV prevalence in which HIV vaccine trials are taking place. Themes were identified from focus group transcripts by four researchers, and included necessity of guardian consent, age of independent consent, and confidentiality of in-trial medical results. In general, ethical adolescent HIV vaccine trials will be feasible in this community.

Achieving an HIV vaccine: the need for an accelerated national campaign.

Science.gov (United States)

Marlink, R

1997-11-01

The development of an effective HIV vaccine has become a crucial national healthcare goal. To develop a worldwide AIDS vaccine, an international collaboration with developing countries is needed. The global approach rationale is threefold: millions of lives can be saved, a vaccine preparation can be tested more rapidly and economically among populations with high rates of infections; and the HIV epidemic comprises at least ten different subtypes. Although a number of barriers to the successful development of an HIV vaccine exist, the polio vaccine can be used as an example to show researchers how to overcome the obstacles. Jonas Salk, the polio vaccine developer, used killed whole virus in a technique that critics argued would not be fully effective. However, the Salk vaccine reduced polio-related paralysis by 72 percent, while the more effective Sabin oral vaccine did not become available until several years later. The lesson to be learned is that any percent of effectiveness is better than nothing, and researchers should not abandon uncertain HIV vaccine development efforts because they believe a better solution may develop in the future. The existence of traditional research should not preclude the development of new solutions that might prove more effective. For example, in the case of polio, the March of Dimes campaign pushed both the Salk and Sabin vaccines despite the skepticism of many academic research groups.

Designing and testing broadly-protective filoviral vaccines optimized for cytotoxic T-lymphocyte epitope coverage.

Directory of Open Access Journals (Sweden)

Paul W Fenimore

Full Text Available We report the rational design and in vivo testing of mosaic proteins for a polyvalent pan-filoviral vaccine using a computational strategy designed for the Human Immunodeficiency Virus type 1 (HIV-1 but also appropriate for Hepatitis C virus (HCV and potentially other diverse viruses. Mosaics are sets of artificial recombinant proteins that are based on natural proteins. The recombinants are computationally selected using a genetic algorithm to optimize the coverage of potential cytotoxic T lymphocyte (CTL epitopes. Because evolutionary history differs markedly between HIV-1 and filoviruses, we devised an adapted computational technique that is effective for sparsely sampled taxa; our first significant result is that the mosaic technique is effective in creating high-quality mosaic filovirus proteins. The resulting coverage of potential epitopes across filovirus species is superior to coverage by any natural variants, including current vaccine strains with demonstrated cross-reactivity. The mosaic cocktails are also robust: mosaics substantially outperformed natural strains when computationally tested against poorly sampled species and more variable genes. Furthermore, in a computational comparison of cross-reactive potential a design constructed prior to the Bundibugyo outbreak performed nearly as well against all species as an updated design that included Bundibugyo. These points suggest that the mosaic designs would be more resilient than natural-variant vaccines against future Ebola outbreaks dominated by novel viral variants. We demonstrate in vivo immunogenicity and protection against a heterologous challenge in a mouse model. This design work delineates the likely requirements and limitations on broadly-protective filoviral CTL vaccines.

Designing and testing broadly-protective filoviral vaccines optimized for cytotoxic T-lymphocyte epitope coverage.

Science.gov (United States)

Fenimore, Paul W; Muhammad, Majidat A; Fischer, William M; Foley, Brian T; Bakken, Russell R; Thurmond, James R; Yusim, Karina; Yoon, Hyejin; Parker, Michael; Hart, Mary Kate; Dye, John M; Korber, Bette; Kuiken, Carla

2012-01-01

We report the rational design and in vivo testing of mosaic proteins for a polyvalent pan-filoviral vaccine using a computational strategy designed for the Human Immunodeficiency Virus type 1 (HIV-1) but also appropriate for Hepatitis C virus (HCV) and potentially other diverse viruses. Mosaics are sets of artificial recombinant proteins that are based on natural proteins. The recombinants are computationally selected using a genetic algorithm to optimize the coverage of potential cytotoxic T lymphocyte (CTL) epitopes. Because evolutionary history differs markedly between HIV-1 and filoviruses, we devised an adapted computational technique that is effective for sparsely sampled taxa; our first significant result is that the mosaic technique is effective in creating high-quality mosaic filovirus proteins. The resulting coverage of potential epitopes across filovirus species is superior to coverage by any natural variants, including current vaccine strains with demonstrated cross-reactivity. The mosaic cocktails are also robust: mosaics substantially outperformed natural strains when computationally tested against poorly sampled species and more variable genes. Furthermore, in a computational comparison of cross-reactive potential a design constructed prior to the Bundibugyo outbreak performed nearly as well against all species as an updated design that included Bundibugyo. These points suggest that the mosaic designs would be more resilient than natural-variant vaccines against future Ebola outbreaks dominated by novel viral variants. We demonstrate in vivo immunogenicity and protection against a heterologous challenge in a mouse model. This design work delineates the likely requirements and limitations on broadly-protective filoviral CTL vaccines.

Hepatitis B and A vaccination in HIV-infected adults: A review.

Science.gov (United States)

Mena, G; García-Basteiro, A L; Bayas, J M

2015-01-01

Hepatitis B and A account for considerable morbidity and mortality worldwide. Immunization is the most effective means of preventing hepatitis B and A. However, the immune response to both hepatitis vaccines seems to be reduced in HIV-infected subjects. The aim of this review was to analyze the immunogenicity, safety, long-term protection and current recommendations of hepatitis B and A vaccination among HIV-infected adults. The factors most frequently associated with a deficient level of anti-HBs or IgG anti-HAV after vaccination are those related to immunosuppression (CD4 level and HIV RNA viral load) and to the frequency of administration and/or the amount of antigenic load per dose. The duration of the response to both HBV and HAV vaccines is associated with suppression of the viral load at vaccination and, in the case of HBV vaccination, with a higher level of antibodies after vaccination. In terms of safety, there is no evidence of more, or different, adverse effects compared with HIV-free individuals. Despite literature-based advice on the administration of alternative schedules, revaccination after the failure of primary vaccination, and the need for periodic re-evaluation of antibody levels, few firm recommendations are found in the leading guidelines.

Hepatitis B and A vaccination in HIV-infected adults: A review

Science.gov (United States)

Mena, G; García-Basteiro, AL; Bayas, JM

2015-01-01

Hepatitis B and A account for considerable morbidity and mortality worldwide. Immunization is the most effective means of preventing hepatitis B and A. However, the immune response to both hepatitis vaccines seems to be reduced in HIV-infected subjects. The aim of this review was to analyze the immunogenicity, safety, long-term protection and current recommendations of hepatitis B and A vaccination among HIV-infected adults. The factors most frequently associated with a deficient level of anti-HBs or IgG anti-HAV after vaccination are those related to immunosuppression (CD4 level and HIV RNA viral load) and to the frequency of administration and/or the amount of antigenic load per dose. The duration of the response to both HBV and HAV vaccines is associated with suppression of the viral load at vaccination and, in the case of HBV vaccination, with a higher level of antibodies after vaccination. In terms of safety, there is no evidence of more, or different, adverse effects compared with HIV-free individuals. Despite literature-based advice on the administration of alternative schedules, revaccination after the failure of primary vaccination, and the need for periodic re-evaluation of antibody levels, few firm recommendations are found in the leading guidelines. PMID:26208678

High-level immunogenicity is achieved vaccine with adjuvanted pandemic H1N1(2009) and improved with booster dosing in a randomized trial of HIV-infected adults.

Science.gov (United States)

Cooper, Curtis; Klein, Marina; Walmsley, Sharon; Haase, David; MacKinnon-Cameron, Donna; Marty, Kimberley; Li, Yan; Smith, Bruce; Halperin, Scott; Law, Barb; Scheifele, David

2012-01-01

More severe influenza disease and poor vaccine immunogenicity in HIV-infected patients necessitate improved immunization strategies to maximize vaccine efficacy. A phase III, randomized trial was conducted at 4 Canadian sites. Two dosing strategies (standard dose vs standard dose plus booster on day 21) were assessed in HIV patients aged 20 to 59 years during the H1N1(2009) pandemic. A single antigen, inactivated split adjuvanted (AS03(A)) influenza vaccine (Arepanrix) was utilized. Serum hemagglutination inhibition (HAI) titres were assessed at days 21 and 42 and at month 6. 150 participants received at least one injection. Baseline parameters were similar between groups: 83% male, 85% on HAART, median CD4 = 519 cells/mm(3), 84% with HIV RNA < 50 copies/mL. At day 21, seroprotection (HAI ≥1:40) was achieved in 80% (95% CI, 70-89) of participants. Seroconversion occurred in 74% (63-85). Seroprotection and seroconversion were further improved in those randomized to booster dosing: day 42, 94% (85-98) versus 73% (60-83) (P < .01) and 86% (75-93) versus 66% (5-77) (P = .01). Seroprotec-tion was retained in 40% (28-54) of recipients at month 6 with trends toward greater retention of immunity in booster recipients. High-level immunogenicity was achieved with a single dose of this adjuvanted vaccine. Immunogenicity was further improved with booster dosing. Use of this adjuvanted vaccine and booster represent an important approach to increasing immunogenicity in this vaccine hypo-responsive population.

Development of Th1 Imprints to rBCG Expressing a Foreign Protein: Implications for Vaccination against HIV-1 and Diverse Influenza Strains

Directory of Open Access Journals (Sweden)

Carl Power

2010-01-01

Full Text Available We demonstrate here that immunizing naïve mice with low numbers of recombinant Bacille Calmette-Guérin (rBCG expressing β-galactosidase (β-gal generates predominant Th1 responses to both BCG and β-gal whereas infection with high numbers generates a mixed Th1/Th2 response to both BCG and β-gal. Furthermore, the Th1 response to both BCG and β-gal is stable when mice, pre-exposed to low numbers of rBCG, are challenged four months later with high numbers of rBCG. Thus the Th1/Th2 phenotypes of the immune responses to β-gal and to BCG are “coherently” regulated. Such rBCG vectors, encoding antigens of pathogens preferentially susceptible to cell-mediated attack, may be useful in vaccinating against such pathogens. We discuss vaccination strategies employing rBCG vectors that are designed to provide protection against diverse influenza strains or numerous variants of HIV-1 and consider what further experiments are essential to explore the possibility of realizing such strategies.

Induction of IL21 in Peripheral T Follicular Helper Cells Is an Indicator of Influenza Vaccine Response in a Previously Vaccinated HIV-Infected Pediatric Cohort.

Science.gov (United States)

de Armas, Lesley R; Cotugno, Nicola; Pallikkuth, Suresh; Pan, Li; Rinaldi, Stefano; Sanchez, M Celeste; Gonzalez, Louis; Cagigi, Alberto; Rossi, Paolo; Palma, Paolo; Pahwa, Savita

2017-03-01

HIV-infected patients of all ages frequently underperform in response to seasonal influenza vaccination, despite virologic control of HIV. The molecular mechanisms governing this impairment, as well as predictive biomarkers for responsiveness, remain unknown. This study was performed in samples obtained prevaccination (T0) from HIV-infected children who received the 2012-2013 seasonal influenza vaccine. Response status was determined based on established criterion for hemagglutination inhibition titer; participants with a hemagglutination titer ≥1:40 plus a ≥4-fold increase over T0 at 3 wk postvaccination were designated as responders. All children had a history of prior influenza vaccinations. At T0, the frequencies of CD4 T cell subsets, including peripheral T follicular helper (pTfh) cells, which provide help to B cells for developing into Ab-secreting cells, were similar between responders and nonresponders. However, in response to in vitro stimulation with influenza A/California/7/2009 (H1N1) Ag, differential gene expression related to pTfh cell function was observed by Fluidigm high-density RT-PCR between responders and nonresponders. In responders, H1N1 stimulation at T0 also resulted in CXCR5 induction (mRNA and protein) in CD4 T cells and IL21 gene induction in pTfh cells that were strongly associated with H1N1-specific B cell responses postvaccination. In contrast, CD4 T cells of nonresponders exhibited increased expression of IL2 and STAT5 genes, which are known to antagonize peripheral Tfh cell function. These results suggest that the quality of pTfh cells at the time of immunization is important for influenza vaccine responses and provide a rationale for targeted, ex vivo Ag-driven molecular profiling of purified immune cells to detect predictive biomarkers of the vaccine response. Copyright © 2017 by The American Association of Immunologists, Inc.

Pre-existing adenovirus immunity modifies a complex mixed Th1 and Th2 cytokine response to an Ad5/HIV-1 vaccine candidate in humans.

Directory of Open Access Journals (Sweden)

Samuel O Pine

2011-04-01

Full Text Available The results of the recent Step Study highlight a need to clarify the effects of pre-existing natural immunity to a vaccine vector on vaccine-induced T-cell responses. To investigate this interaction, we examined the relationship between pre-existing Ad5 immunity and T-cell cytokine response profiles in healthy, HIV-uninfected recipients of MRKAd5 HIV-1 gag vaccine (HVTN 050, ClinicalTrials.gov #NCT00849732. Participants were grouped by baseline Ad5 neutralizing antibody titer as either Ad5-seronegative (titer ≤18; n = 36 or Ad5-seropositive (titer >200; n = 34. Samples from vaccine recipients were analyzed for immune responses to either HIV-1 Gag peptide pools or Ad5 empty vector using an ex vivo assay that measures thirty cytokines in the absence of long-term culture. The overall profiles of cytokine responses to Gag and Ad5 had similar combinations of induced Th1- and Th2-type cytokines, including IFN-γ, IL-2, TNF-α, IP-10, IL-13, and IL-10, although the Ad5-specific responses were uniformly higher than the Gag-specific responses (p<0.0001 for 9 out of 11 significantly expressed analytes. At the peak response time point, PBMC from Ad5-seronegative vaccinees secreted significantly more IP-10 in response to Gag (p = 0.008, and significantly more IP-10 (p = 0.0009, IL-2 (p = 0.006 and IL-10 (p = 0.05 in response to Ad5 empty vector than PBMC from Ad5-seropositive vaccinees. Additionally, similar responses to the Ad5 vector prior to vaccination were observed in almost all subjects, regardless of Ad5 neutralizing antibody status, and the levels of secreted IFN-γ, IL-10, IL-1Ra and GM-CSF were blunted following vaccination. The cytokine response profile of Gag-specific T cells mirrored the Ad5-specific response present in all subjects before vaccination, and included a number of Th1- and Th2-associated cytokines not routinely assessed in current vaccine trials, such as IP-10, IL-10, IL-13, and GM-CSF. Together, these

A Phase I Double Blind, Placebo-Controlled, Randomized Study of the Safety and Immunogenicity of Electroporated HIV DNA with or without Interleukin 12 in Prime-Boost Combinations with an Ad35 HIV Vaccine in Healthy HIV-Seronegative African Adults.

Directory of Open Access Journals (Sweden)

Juliet Mpendo

Full Text Available Strategies to enhance the immunogenicity of DNA vaccines in humans include i co-administration of molecular adjuvants, ii intramuscular administration followed by in vivo electroporation (IM/EP and/or iii boosting with a different vaccine. Combining these strategies provided protection of macaques challenged with SIV; this clinical trial was designed to mimic the vaccine regimen in the SIV study.Seventy five healthy, HIV-seronegative adults were enrolled into a phase 1, randomized, double-blind, placebo-controlled trial. Multi-antigenic HIV (HIVMAG plasmid DNA (pDNA vaccine alone or co-administered with pDNA encoding human Interleukin 12 (IL-12 (GENEVAX IL-12 given by IM/EP using the TriGrid Delivery System was tested in different prime-boost regimens with recombinant Ad35 HIV vaccine given IM.All local reactions but one were mild or moderate. Systemic reactions and unsolicited adverse events including laboratory abnormalities did not differ between vaccine and placebo recipients. No serious adverse events (SAEs were reported. T cell and antibody response rates after HIVMAG (x3 prime-Ad35 (x1 boost were independent of IL-12, while the magnitude of interferon gamma (IFN-γ ELISPOT responses was highest after HIVMAG (x3 without IL-12. The quality and phenotype of T cell responses shown by intracellular cytokine staining (ICS were similar between groups. Inhibition of HIV replication by autologous T cells was demonstrated after HIVMAG (x3 prime and was boosted after Ad35. HIV specific antibodies were detected only after Ad35 boost, although there was a priming effect with 3 doses of HIVMAG with or without IL-12. No anti-IL-12 antibodies were detected.The vaccines were safe, well tolerated and moderately immunogenic. Repeated administration IM/EP was well accepted. An adjuvant effect of co-administered plasmid IL-12 was not detected.ClinicalTrials.gov NCT01496989.

Use of an in vivo FTA assay to assess the magnitude, functional avidity and epitope variant cross-reactivity of T cell responses following HIV-1 recombinant poxvirus vaccination.

Directory of Open Access Journals (Sweden)

Danushka K Wijesundara

Full Text Available Qualitative characteristics of cytotoxic CD8+ T cells (CTLs are important in measuring the effectiveness of CTLs in controlling HIV-1 infections. Indeed, in recent studies patients who are naturally resistant to HIV-1 infections have been shown to possess CTLs that are of high functional avidity and have a high capacity to recognize HIV epitope variants, when compared to HIV-1 infection progressors. When developing efficacious vaccines, assays that can effectively measure CTL quality specifically in vivo are becoming increasingly important. Here we report the use of a recently developed high-throughput multi-parameter technique, known as the fluorescent target array (FTA assay, to simultaneously measure CTL killing magnitude, functional avidity and epitope variant cross-reactivity in real time in vivo. In the current study we have applied the FTA assay as a screening tool to assess a large cohort of over 20 different HIV-1 poxvirus vaccination strategies in mice. This screen revealed that heterologous poxvirus prime-boost vaccination regimes (i.e., recombinant fowlpox (FPV-HIV prime followed by a recombinant vaccinia virus (VV-HIV booster were the most effective in generating high quality CTL responses in vivo. In conclusion, we have demonstrated how the FTA assay can be utilized as a cost effective screening tool (by reducing the required number of animals by >100 fold, to evaluate a large range of HIV-1 vaccination strategies in terms of CTL avidity and variant cross-reactivity in an in vivo setting.

Use of an in vivo FTA assay to assess the magnitude, functional avidity and epitope variant cross-reactivity of T cell responses following HIV-1 recombinant poxvirus vaccination.

Science.gov (United States)

Wijesundara, Danushka K; Ranasinghe, Charani; Jackson, Ronald J; Lidbury, Brett A; Parish, Christopher R; Quah, Benjamin J C

2014-01-01

Qualitative characteristics of cytotoxic CD8+ T cells (CTLs) are important in measuring the effectiveness of CTLs in controlling HIV-1 infections. Indeed, in recent studies patients who are naturally resistant to HIV-1 infections have been shown to possess CTLs that are of high functional avidity and have a high capacity to recognize HIV epitope variants, when compared to HIV-1 infection progressors. When developing efficacious vaccines, assays that can effectively measure CTL quality specifically in vivo are becoming increasingly important. Here we report the use of a recently developed high-throughput multi-parameter technique, known as the fluorescent target array (FTA) assay, to simultaneously measure CTL killing magnitude, functional avidity and epitope variant cross-reactivity in real time in vivo. In the current study we have applied the FTA assay as a screening tool to assess a large cohort of over 20 different HIV-1 poxvirus vaccination strategies in mice. This screen revealed that heterologous poxvirus prime-boost vaccination regimes (i.e., recombinant fowlpox (FPV)-HIV prime followed by a recombinant vaccinia virus (VV)-HIV booster) were the most effective in generating high quality CTL responses in vivo. In conclusion, we have demonstrated how the FTA assay can be utilized as a cost effective screening tool (by reducing the required number of animals by >100 fold), to evaluate a large range of HIV-1 vaccination strategies in terms of CTL avidity and variant cross-reactivity in an in vivo setting.

Low tetanus, diphtheria and acellular pertussis (Tdap) vaccination coverage among HIV infected individuals in Austria.

Science.gov (United States)

Grabmeier-Pfistershammer, K; Herkner, H; Touzeau-Roemer, V; Rieger, A; Burgmann, H; Poeppl, W

2015-07-31

Current management guidelines of HIV infected adults include recommendation to immunization against common vaccine preventable diseases. This effort is hindered by the scarce knowledge regarding the immunization status of this especially vulnerable patient group. This study analyzed the serostatus for pertussis, diphtheria and tetanus of more than 700 HIV infected individuals residing in Austria. These individuals were representative for the Austrian HIV cohort regarding sex, age, transmission risk and HIV progression markers. Overall, 73.6% were on suppressive HAART, mean CD4 cell count was 603c/μl. Seropositivity was 84% for diphtheria, 51% for tetanus and 1% for pertussis. Migrants had a lower chance of tetanus seropositivity (OR 0.30 (CI 0.21 to 0.43)). Increase in CDC classification were associated with increased diphtheria seropositivity (OR 1.42 (CI 1.02 to 1.98)) and a CD4 nadir200c/μl, 95% lacked seroprotection to at least one of the antigens included in the triple vaccine Tdap and could be vaccinated. Thus, a proactive approach would largely reduce the number of patients at risk for these vaccine-preventable diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

The F4/AS01B HIV-1 Vaccine Candidate Is Safe and Immunogenic, But Does Not Show Viral Efficacy in Antiretroviral Therapy-Naive, HIV-1-Infected Adults: A Randomized Controlled Trial.

Science.gov (United States)

Dinges, Warren; Girard, Pierre-Marie; Podzamczer, Daniel; Brockmeyer, Norbert H; García, Felipe; Harrer, Thomas; Lelievre, Jean-Daniel; Frank, Ian; Colin De Verdière, Nathalie; Yeni, Guy-Patrick; Ortega Gonzalez, Enrique; Rubio, Rafael; Clotet Sala, Bonaventura; DeJesus, Edwin; Pérez-Elias, Maria Jesus; Launay, Odile; Pialoux, Gilles; Slim, Jihad; Weiss, Laurence; Bouchaud, Olivier; Felizarta, Franco; Meurer, Anja; Raffi, François; Esser, Stefan; Katlama, Christine; Koletar, Susan L; Mounzer, Karam; Swindells, Susan; Baxter, John D; Schneider, Stefan; Chas, Julie; Molina, Jean-Michel; Koutsoukos, Marguerite; Collard, Alix; Bourguignon, Patricia; Roman, François

2016-02-01

The impact of the investigational human immunodeficiency virus type 1 (HIV-1) F4/AS01B vaccine on HIV-1 viral load (VL) was evaluated in antiretroviral therapy (ART)-naive HIV-1 infected adults.This phase IIb, observer-blind study (NCT01218113), included ART-naive HIV-1 infected adults aged 18 to 55 years. Participants were randomized to receive 2 (F4/AS01B_2 group, N = 64) or 3 (F4/AS01B_3 group, N = 62) doses of F4/AS01B or placebo (control group, N = 64) at weeks 0, 4, and 28. Efficacy (HIV-1 VL, CD4 T-cell count, ART initiation, and HIV-related clinical events), safety, and immunogenicity (antibody and T-cell responses) were evaluated during 48 weeks.At week 48, based on a mixed model, no statistically significant difference in HIV-1 VL change from baseline was demonstrated between F4/AS01B_2 and control group (0.073 log10 copies/mL [97.5% confidence interval (CI): -0.088; 0.235]), or F4/AS01B_3 and control group (-0.096 log10 copies/mL [97.5% CI: -0.257; 0.065]). No differences between groups were observed in HIV-1 VL change, CD4 T-cell count, ART initiation, or HIV-related clinical events at intermediate timepoints. Among F4/AS01B recipients, the most frequent solicited symptoms were pain at injection site (252/300 doses), fatigue (137/300 doses), myalgia (105/300 doses), and headache (90/300 doses). Twelve serious adverse events were reported in 6 participants; 1 was considered vaccine-related (F4/AS01B_2 group: angioedema). F4/AS01B induced polyfunctional F4-specific CD4 T-cells, but had no significant impact on F4-specific CD8 T-cell and anti-F4 antibody levels.F4/AS01B had a clinically acceptable safety profile, induced F4-specific CD4 T-cell responses, but did not reduce HIV-1 VL, impact CD4 T-cells count, delay ART initiation, or prevent HIV-1 related clinical events.

Motivators to participation in actual HIV vaccine trials.

Science.gov (United States)

Dhalla, Shayesta; Poole, Gary

2014-02-01

An examination of actual HIV vaccine trials can contribute to an understanding of motivators for participation in these studies. Analysis of these motivators reveals that they can be categorized as social and personal benefits. Social benefits are generally altruistic, whereas personal benefits are psychological, physical, and financial. In this systematic review, the authors performed a literature search for actual preventive HIV vaccine trials reporting motivators to participation. Of studies conducted in the Organization for Economic Co-operation and Development (OECD) countries, the authors retrieved 12 studies reporting on social benefits and seven reporting on personal benefits. From the non-OECD countries, nine studies reported on social benefits and eight studies on personal benefits. Social benefits were most frequently described on macroscopic, altruistic levels. Personal benefits were most frequently psychological in nature. Rates of participation were compared between the OECD and the non-OECD countries. Knowledge of actual motivators in specific countries and regions can help target recruitment in various types of actual HIV vaccine trials.

HIV vaccine trials: critical issues in informed consent.

Science.gov (United States)

Lindegger, G; Richter, L M

2000-06-01

Informed consent (IC), a fundamental principle of ethics in medical research, is recognized as a vital component of HIV vaccine trials. There are different notions of IC, some legally based and others based on ethics. It is argued that, though legal indemnity is necessary, vaccine trials should be founded on fully ethical considerations. Various contentious aspects of IC are examined, especially the problem of social desirability and of adequate comprehension. The need for sensitivity to cultural norms in implementing IC procedures is critically reviewed, and some of the potential conflict between ethos and ethics is considered. The transmission of information is examined as a particular aspect of IC in HIV vaccine trials.

Future HIV Vaccine Acceptability among Young Adults in South Africa

Science.gov (United States)

Sayles, Jennifer N.; Macphail, Catherine L.; Newman, Peter A.; Cunningham, William E.

2010-01-01

Developing and disseminating a preventive HIV vaccine is a primary scientific and public health objective. However, little is known about HIV vaccine acceptability in the high-prevalence setting of South Africa--where young adults are likely to be targeted in early dissemination efforts. This study reports on six focus groups (n = 42) conducted in…

HIV-infected children living in Central Africa have low persistence of antibodies to vaccines used in the Expanded Program on Immunization.

Directory of Open Access Journals (Sweden)

Mathurin C Tejiokem

Full Text Available BACKGROUND: The Expanded Program on Immunization (EPI is the most cost-effective measures to control vaccine-preventable diseases. Currently, the EPI schedule is similar for HIV-infected children; the introduction of antiretroviral therapy (ART should considerably prolong their life expectancy. METHODS AND PRINCIPAL FINDINGS: To evaluate the persistence of antibodies to the EPI vaccines in HIV-infected and HIV-exposed uninfected children who previously received these vaccines in routine clinical practice, we conducted a cross-sectional study of children, aged 18 to 36 months, born to HIV-infected mothers and living in Central Africa. We tested blood samples for antibodies to the combined diphtheria, tetanus, and whole-cell pertussis (DTwP, the measles and the oral polio (OPV vaccines. We enrolled 51 HIV-infected children of whom 33 were receiving ART, and 78 HIV-uninfected children born to HIV-infected women. A lower proportion of HIV-infected children than uninfected children had antibodies to the tested antigens with the exception of the OPV types 1 and 2. This difference was substantial for the measles vaccine (20% of the HIV-infected children and 56% of the HIV-exposed uninfected children, p<0.0001. We observed a high risk of low antibody levels for all EPI vaccines, except OPV types 1 and 2, in HIV-infected children with severe immunodeficiency (CD4(+ T cells <25%. CONCLUSIONS AND SIGNIFICANCE: Children were examined at a time when their antibody concentrations to EPI vaccines would have still not undergone significant decay. However, we showed that the antibody concentrations were lowered in HIV-infected children. Moreover, antibody concentration after a single dose of the measles vaccine was substantially lower than expected, particularly low in HIV-infected children with low CD4(+ T cell counts. This study supports the need for a second dose of the measles vaccine and for a booster dose of the DTwP and OPV vaccines to maintain the

Therapeutic DNA vaccination of vertically HIV-infected children: report of the first pediatric randomised trial (PEDVAC).

Science.gov (United States)

Palma, Paolo; Romiti, Maria Luisa; Montesano, Carla; Santilli, Veronica; Mora, Nadia; Aquilani, Angela; Dispinseri, Stefania; Tchidjou, Hyppolite K; Montano, Marco; Eriksson, Lars E; Baldassari, Stefania; Bernardi, Stefania; Scarlatti, Gabriella; Wahren, Britta; Rossi, Paolo

2013-01-01

Twenty vertically HIV-infected children, 6-16 years of age, with stable viral load control and CD4+ values above 400 cells/mm(3). Ten subjects continued their ongoing antiretroviral treatment (ART, Group A) and 10 were immunized with a HIV-DNA vaccine in addition to their previous therapy (ART and vaccine, Group B). The genetic vaccine represented HIV-1 subtypes A, B and C, encoded Env, Rev, Gag and RT and had no additional adjuvant. Immunizations took place at weeks 0, 4 and 12, with a boosting dose at week 36. Monitoring was performed until week 60 and extended to week 96. Safety data showed good tolerance of the vaccine. Adherence to ART remained high and persistent during the study and did not differ significantly between controls and vaccinees. Neither group experienced either virological failure or a decline of CD4+ counts from baseline. Higher HIV-specific cellular immune responses were noted transiently to Gag but not to other components of the vaccine. Lymphoproliferative responses to a virion antigen HIV-1 MN were higher in the vaccinees than in the controls (p = 0.047), whereas differences in reactivity to clade-specific Gag p24, RT or Env did not reach significance. Compared to baseline, the percentage of HIV-specific CD8+ lymphocytes releasing perforin in the Group B was higher after the vaccination schedule had been completed (p = 0.031). No increased CD8+ perforin levels were observed in control Group A. The present study demonstrates the feasibility, safety and moderate immunogenicity of genetic vaccination in vertically HIV-infected children, paving the way for amplified immunotherapeutic approaches in the pediatric population. clinicaltrialsregister.eu _2007-002359-18IT.

Therapeutic DNA vaccination of vertically HIV-infected children: report of the first pediatric randomised trial (PEDVAC.

Directory of Open Access Journals (Sweden)

Paolo Palma

Full Text Available SUBJECTS: Twenty vertically HIV-infected children, 6-16 years of age, with stable viral load control and CD4+ values above 400 cells/mm(3. INTERVENTION: Ten subjects continued their ongoing antiretroviral treatment (ART, Group A and 10 were immunized with a HIV-DNA vaccine in addition to their previous therapy (ART and vaccine, Group B. The genetic vaccine represented HIV-1 subtypes A, B and C, encoded Env, Rev, Gag and RT and had no additional adjuvant. Immunizations took place at weeks 0, 4 and 12, with a boosting dose at week 36. Monitoring was performed until week 60 and extended to week 96. RESULTS: Safety data showed good tolerance of the vaccine. Adherence to ART remained high and persistent during the study and did not differ significantly between controls and vaccinees. Neither group experienced either virological failure or a decline of CD4+ counts from baseline. Higher HIV-specific cellular immune responses were noted transiently to Gag but not to other components of the vaccine. Lymphoproliferative responses to a virion antigen HIV-1 MN were higher in the vaccinees than in the controls (p = 0.047, whereas differences in reactivity to clade-specific Gag p24, RT or Env did not reach significance. Compared to baseline, the percentage of HIV-specific CD8+ lymphocytes releasing perforin in the Group B was higher after the vaccination schedule had been completed (p = 0.031. No increased CD8+ perforin levels were observed in control Group A. CONCLUSIONS: The present study demonstrates the feasibility, safety and moderate immunogenicity of genetic vaccination in vertically HIV-infected children, paving the way for amplified immunotherapeutic approaches in the pediatric population. TRIAL REGISTRATION: clinicaltrialsregister.eu _2007-002359-18IT.

Characterization of functional antibody and memory B-cell responses to pH1N1 monovalent vaccine in HIV-infected children and youth.

Directory of Open Access Journals (Sweden)

Donna J Curtis

Full Text Available We investigated immune determinants of antibody responses and B-cell memory to pH1N1 vaccine in HIV-infected children.Ninety subjects 4 to <25 years of age received two double doses of pH1N1 vaccine. Serum and cells were frozen at baseline, after each vaccination, and at 28 weeks post-immunization. Hemagglutination inhibition (HAI titers, avidity indices (AI, B-cell subsets, and pH1N1 IgG and IgA antigen secreting cells (ASC were measured at baseline and after each vaccination. Neutralizing antibodies and pH1N1-specific Th1, Th2 and Tfh cytokines were measured at baseline and post-dose 1.At entry, 26 (29% subjects had pH1N1 protective HAI titers (≥1:40. pH1N1-specific HAI, neutralizing titers, AI, IgG ASC, IL-2 and IL-4 increased in response to vaccination (p<0.05, but IgA ASC, IL-5, IL-13, IL-21, IFNγ and B-cell subsets did not change. Subjects with baseline HAI ≥1:40 had significantly greater increases in IgG ASC and AI after immunization compared with those with HAI <1:40. Neutralizing titers and AI after vaccination increased with older age. High pH1N1 HAI responses were associated with increased IgG ASC, IFNγ, IL-2, microneutralizion titers, and AI. Microneutralization titers after vaccination increased with high IgG ASC and IL-2 responses. IgG ASC also increased with high IFNγ responses. CD4% and viral load did not predict the immune responses post-vaccination, but the B-cell distribution did. Notably, vaccine immunogenicity increased with high CD19+CD21+CD27+% resting memory, high CD19+CD10+CD27+% immature activated, low CD19+CD21-CD27-CD20-% tissue-like, low CD19+CD21-CD27-CD20-% transitional and low CD19+CD38+HLADR+% activated B-cell subsets.HIV-infected children on HAART mount a broad B-cell memory response to pH1N1 vaccine, which was higher for subjects with baseline HAI≥1:40 and increased with age, presumably due to prior exposure to pH1N1 or to other influenza vaccination/infection. The response to the vaccine was dependent

Beyond the checklist: assessing understanding for HIV vaccine trial participation in South Africa.

Science.gov (United States)

Lindegger, Graham; Milford, Cecilia; Slack, Catherine; Quayle, Michael; Xaba, Xolani; Vardas, Eftyhia

2006-12-15

Informed consent and understanding are essential ethical requirements for clinical trial participation. Traditional binary measures of understanding may be limited and not be the best measures of level of understanding. This study designed and compared 4 measures of understanding for potential participants being prepared for enrollment in South African HIV vaccine trials, using detailed operational scoring criteria. Assessment of understanding of 7 key trial components was compared via self-report, checklist, vignettes, and narrative measures. Fifty-nine participants, including members of vaccine preparedness groups and 1 HIV vaccine trial, took part. There were significant differences across the measures for understanding of 5 components and for overall understanding. Highest scores were obtained on self-report and checklist measures, and lowest scores were obtained for vignettes and narrative descriptions. The findings suggest that levels of measured understanding are dependent on the tools used. Forced-choice measures like checklists tend to yield higher scores than open-ended measures like narratives or vignettes. Consideration should be given to complementing checklists and self-reports with open-ended measures, particularly for critical trial concepts, where the consequences of misunderstanding are potentially severe.

HIV vaccines in Canada: legal and ethical issues--an overview.

Science.gov (United States)

Garmaise, David

2002-07-01

In July 2002 the Legal Network released an overview paper on legal and ethical issues related to an HIV vaccine in Canada. The paper, which is based on a more detailed report prepared in collaboration with the Centre for Bioethics of the Clinical Research Institute of Montréal, calls for the establishment of a Canadian HIV Vaccine Plan.

A New Scientific Paradigm may be Needed to Finally Develop an HIV Vaccine.

Science.gov (United States)

Esparza, José

2015-01-01

The bulk of current HIV vaccine research is conducted within the infectious disease paradigm that has been very successful in developing vaccines against many other viral diseases. Different HIV vaccine concepts, based on the induction of neutralizing antibodies and/or cell mediated immunity, have been developed and clinically tested over the last 30 years, resulting in a few small successes and many disappointments. As new scientific knowledge is obtained, HIV vaccine concepts are constantly modified with the hope that the newly introduced tweaks (or paradigm drifts) will provide the solution to one of the most difficult challenges that modern biomedical research is confronting. Efficacy trials have been critical in guiding HIV vaccine development. However, from the five phase III efficacy trials conducted to date, only one (RV144) resulted in modest efficacy. The results from RV144 were surprising in many ways, including the identified putative correlates of protection (or risk), which did not include neutralizing antibodies or cytotoxic T-cells. The solution to the HIV vaccine challenge may very well come from approaches based on the current paradigm. However, at the same time, out-of-the-paradigm ideas should be systematically explored to complement the current efforts. New mechanisms are needed to identify and support the innovative research that will hopefully accelerate the development of an urgently needed HIV vaccine.

Biocompatible anionic polymeric microspheres as priming delivery system for effetive HIV/AIDS Tat-based vaccines.

Directory of Open Access Journals (Sweden)

Fausto Titti

Full Text Available Here we describe a prime-boost regimen of vaccination in Macaca fascicularis that combines priming with novel anionic microspheres designed to deliver the biologically active HIV-1 Tat protein and boosting with Tat in Alum. This regimen of immunization modulated the IgG subclass profile and elicited a balanced Th1-Th2 type of humoral and cellular responses. Remarkably, following intravenous challenge with SHIV89.6Pcy243, vaccinees significantly blunted acute viremia, as compared to control monkeys, and this control was associated with significantly lower CD4+ T cell depletion rate during the acute phase of infection and higher ability to resume the CD4+ T cell counts in the post-acute and chronic phases of infection. The long lasting control of viremia was associated with the persistence of high titers anti-Tat antibodies whose profile clearly distinguished vaccinees in controllers and viremics. Controllers, as opposed to vaccinated and viremic cynos, exhibited significantly higher pre-challenge antibody responses to peptides spanning the glutamine-rich and the RGD-integrin-binding regions of Tat. Finally, among vaccinees, titers of anti-Tat IgG1, IgG3 and IgG4 subclasses had a significant association with control of viremia in the acute and post-acute phases of infection. Altogether these findings indicate that the Tat/H1D/Alum regimen of immunization holds promise for next generation vaccines with Tat protein or other proteins for which maintenance of the native conformation and activity are critical for optimal immunogenicity. Our results also provide novel information on the role of anti-Tat responses in the prevention of HIV pathogenesis and for the design of new vaccine candidates.

Diphtheria, tetanus, poliomyelitis, yellow fever and hepatitis B seroprevalence among HIV1-infected migrants. Results from the ANRS VIHVO vaccine sub-study.

Science.gov (United States)

Mullaert, Jimmy; Abgrall, Sophie; Lele, Nathalie; Batteux, Frederic; Slama, Lilia Ben; Meritet, Jean-Francois; Lebon, Pierre; Bouchaud, Olivier; Grabar, Sophie; Launay, Odile

2015-09-11

Few data are available on the seroprotection status of HIV1-infected patients with respect to vaccine-preventable diseases. To describe, in a population of HIV1-infected migrants on stable, effective ART therapy, the seroprevalence of diphtheria, poliomyelitis, tetanus, yellow fever antibodies and serostatus for hepatitis B, and to identify factors associated with seroprotection. Vaccine responses against diphtheria, tetanus, poliomyelitis and yellow fever were also studied. Sub-Saharan African patients participating in the ANRS-VIHVO cohort were enrolled prior to travel to their countries of origin. Serologic analyses were performed in a central laboratory before and after the trip. Univariate and multivariate logistic regression was used to identify factors associated with initial seroprotection. 250 patients (99 men and 151 women) were included in the seroprevalence study. Median age was 45 years (IQR 39-52), median CD4 cell count was 440/μL (IQR 336-571), and 237 patients (95%) had undetectable HIV1 viral load. The initial seroprevalence rates were 69.0% (95%CI 63.2-74.7) for diphtheria, 70.7% (95%CI 65.0-76.3) for tetanus, and 85.9% (95%CI 81.6-90.2) for yellow fever. Only 64.4% (95%CI 58.5-70.3) of patients had protective antibody titers against all three poliomyelitis vaccine strains before travel. No serological markers of hepatitis B were found in 18.6% of patients (95%CI 13.7-23.3). Patient declaration of prior vaccination was the only factor consistently associated with initial seroprotection. We found a low prevalence of seroprotection against diphtheria, poliomyelitis, tetanus and hepatitis B. HIV infected migrants living in France and traveling to their native countries need to have their vaccine schedule completed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Immunogenicity and safety of high-dose trivalent inactivated influenza vaccine compared to standard-dose vaccine in children and young adults with cancer or HIV infection.

Science.gov (United States)

Hakim, Hana; Allison, Kim J; Van de Velde, Lee-Ann; Tang, Li; Sun, Yilun; Flynn, Patricia M; McCullers, Jonathan A

2016-06-08

Approaches to improve the immune response of immunocompromised patients to influenza vaccination are needed. Children and young adults (3-21 years) with cancer or HIV infection were randomized to receive 2 doses of high-dose (HD) trivalent influenza vaccine (TIV) or of standard-dose (SD) TIV. Hemagglutination inhibition (HAI) antibody titers were measured against H1, H3, and B antigens after each dose and 9 months later. Seroconversion was defined as ≥4-fold rise in HAI titer comparing pre- and post-vaccine sera. Seroprotection was defined as a post-vaccine HAI titer ≥1:40. Reactogenicity events (RE) were solicited using a structured questionnaire 7 and 14 days after each dose of vaccine, and adverse events by medical record review for 21 days after each dose of vaccine. Eighty-five participants were enrolled in the study; 27 with leukemia, 17 with solid tumor (ST), and 41 with HIV. Recipients of HD TIV had significantly greater fold increase in HAI titers to B antigen in leukemia group and to H1 antigen in ST group compared to SD TIV recipients. This increase was not documented in HIV group. There were no differences in seroconversion or seroprotection between HD TIV and SD TIV in all groups. There was no difference in the percentage of solicited RE in recipients of HD TIV (54% after dose 1 and 38% after dose 2) compared to SD TIV (40% after dose 1 and 20% after dose 2, p=0.27 and 0.09 after dose 1 and 2, respectively). HD TIV was more immunogenic than SD TIV in children and young adults with leukemia or ST, but not with HIV. HD TIV was safe and well-tolerated in children and young adults with leukemia, ST, or HIV. Copyright © 2016 Elsevier Ltd. All rights reserved.

On modeling HIV and T cells in vivo: assessing causal estimators in vaccine trials.

Directory of Open Access Journals (Sweden)

W David Wick

2006-06-01

Full Text Available The first efficacy trials--named STEP--of a T cell vaccine against HIV/AIDS began in 2004. The unprecedented structure of these trials raised new modeling and statistical challenges. Is it plausible that memory T cells, as opposed to antibodies, can actually prevent infection? If they fail at prevention, to what extent can they ameliorate disease? And how do we estimate efficacy in a vaccine trial with two primary endpoints, one traditional, one entirely novel (viral load after infection, and where the latter may be influenced by selection bias due to the former? In preparation for the STEP trials, biostatisticians developed novel techniques for estimating a causal effect of a vaccine on viral load, while accounting for post-randomization selection bias. But these techniques have not been tested in biologically plausible scenarios. We introduce new stochastic models of T cell and HIV kinetics, making use of new estimates of the rate that cytotoxic T lymphocytes--CTLs; the so-called killer T cells--can kill HIV-infected cells. Based on these models, we make the surprising discovery that it is not entirely implausible that HIV-specific CTLs might prevent infection--as the designers explicitly acknowledged when they chose the endpoints of the STEP trials. By simulating thousands of trials, we demonstrate that the new statistical methods can correctly identify an efficacious vaccine, while protecting against a false conclusion that the vaccine exacerbates disease. In addition to uncovering a surprising immunological scenario, our results illustrate the utility of mechanistic modeling in biostatistics.

Current Peptide and Protein Candidates Challenging HIV Therapy beyond the Vaccine Era

Directory of Open Access Journals (Sweden)

Koollawat Chupradit

2017-09-01

Full Text Available Human immunodeficiency virus (HIV is a causative agent of acquired immune deficiency syndrome (AIDS. Highly active antiretroviral therapy (HAART can slow down the replication of HIV-1, leading to an improvement in the survival of HIV-1-infected patients. However, drug toxicities and poor drug administration has led to the emergence of a drug-resistant strain. HIV-1 immunotherapy has been continuously developed, but antibody therapy and HIV vaccines take time to improve its efficiency and have limitations. HIV-1-specific chimeric antigen receptor (CAR-based immunotherapy founded on neutralizing antibodies is now being developed. In HIV-1 therapy, anti-HIV chimeric antigen receptors showed promising data in the suppression of HIV-1 replication; however, autologous transfusion is still a problem. This has led to the development of effective peptides and proteins for an alternative HIV-1 treatment. In this paper, we provide a comprehensive review of potent anti-HIV-1 peptides and proteins that reveal promising therapeutic activities. The inhibitory mechanisms of each therapeutic molecule in the different stages of the HIV-1 life cycle will be discussed herein.

A recoding method to improve the humoral immune response to an HIV DNA vaccine.

Directory of Open Access Journals (Sweden)

Yaoxing Huang

Full Text Available This manuscript describes a novel strategy to improve HIV DNA vaccine design. Employing a new information theory based bioinformatic algorithm, we identify a set of nucleotide motifs which are common in the coding region of HIV, but are under-represented in genes that are highly expressed in the human genome. We hypothesize that these motifs contribute to the poor protein expression of gag, pol, and env genes from the c-DNAs of HIV clinical isolates. Using this approach and beginning with a codon optimized consensus gag gene, we recode the nucleotide sequence so as to remove these motifs without modifying the amino acid sequence. Transfecting the recoded DNA sequence into a human kidney cell line results in doubling the gag protein expression level compared to the codon optimized version. We then turn both sequences into DNA vaccines and compare induced antibody response in a murine model. Our sequence, which has the motifs removed, induces a five-fold increase in gag antibody response compared to the codon optimized vaccine.

Vaccinations for Adults with HIV Infection

Science.gov (United States)

... for example, lack of a functioning spleen, need vac- influenzae type b) cination with Hib. Talk to ... of developing severe complications because of your HIV infection. Meningococcal ACWY (Men- ACWY, MCV4) Yes! MenACWY vaccine ...

The impact of inflammation and immune activation on B cell differentiation during HIV-1 infection

Directory of Open Access Journals (Sweden)

Nicolas eRuffin

2012-01-01

Full Text Available HIV-1 infection is characterized by continuous antigenic stimulation, chronic immune activation and impaired survival of T and B cells. A decline of resting memory B cells has previously been reported to occur in both children and adults infected with HIV-1; these cells are responsible for mounting and maintaining an adequate serological response to antigens previously encountered in life through natural infection or vaccination. Further understanding of the mechanisms leading to impaired B cell differentiation and germinal center reaction might be essential to design new HIV vaccines and therapies that could improve humoral immune responses in HIV-1 infected individuals. In the present article we summarize the literature and present our view on critical mechanisms of B cell development which are impaired during HIV-1 infection. We also discuss the impact of microbial translocation, a driving force for persistent inflammation during HIV-1 infection, on survival of terminally differentiated B cells and how the altered expression of cytokines/chemokines pivotal for communication between T and B cells in lymphoid tissues may impair formation of memory B cells.

Enhancement of human immunodeficiency virus type 1-DNA vaccine potency through incorporation of T-helper 1 molecular adjuvants.

Science.gov (United States)

Calarota, Sandra A; Weiner, David B

2004-06-01

It is clear that the development of a safe and effective vaccine for human immunodeficiency virus type 1 (HIV-1) remains a crucial goal for controlling the acquired immunodeficiency syndrome epidemic. At present, it is not clear what arm of the immune response correlates with protection from HIV-1 infection or disease. Therefore, a strong cellular and humoral immune response will likely be needed to control this infection. Among different vaccine alternatives, DNA vaccines appeared more than a decade ago, demonstrating important qualities of inducing both humoral and cellular immune responses in animal models. However, after several years and various clinical studies in humans, supporting the safety of the HIV-DNA vaccine strategies, it has become clear that their potency should be improved. One way to modulate and enhance the immune responses induced by a DNA vaccine is by including genetic adjuvants such as cytokines, chemokines, or T-cell costimulatory molecules as part of the vaccine itself. Particularly, vaccine immunogenicity can be modulated by factors that attract professional antigen-presenting cells, provide additional costimulation, or enhance the uptake of plasmid DNA. This review focuses on developments in the coadministration of molecular adjuvants for the enhancement of HIV-1 DNA-vaccine potency.

HIV vaccine: it may take two to tango, but no party time yet

NARCIS (Netherlands)

Berkhout, Ben; Paxton, William A.

2009-01-01

ABSTRACT: A press conference on Thursday September 24 in Bangkok, Thailand, released data that an experimental vaccine provided mild protection against HIV-1 infection. This is the first positive signal of any degree of vaccine efficacy in humans, more than a quarter-century after scientists

DNA vaccines expressing soluble CD4-envelope proteins fused to C3d elicit cross-reactive neutralizing antibodies to HIV-1

International Nuclear Information System (INIS)

Bower, Joseph F.; Green, Thomas D.; Ross, Ted M.

2004-01-01

DNA vaccines expressing the envelope (Env) of the human immunodeficiency virus type 1 (HIV-1) have been relatively ineffective at generating high-titer, long-lasting, neutralizing antibodies in a variety of animal models. In this study, DNA vaccines were constructed to express a fusion protein of the soluble human CD4 (sCD4) and the gp120 subunit of the HIV-1 envelope. To enhance the immunogenicity of the expressed fusion protein, three copies of the murine C3d (mC3d 3 ) were added to the carboxyl terminus of the complex. Monoclonal antibodies that recognize CD4-induced epitopes on gp120 efficiently bound to sCD4-gp120 or sCD4-gp120-mC3d 3 . In addition, both sCD4-gp120 and sCD4-gp120-mC3d 3 bound to cells expressing appropriate coreceptors in the absence of cell surface hCD4. Mice (BALB/c) vaccinated with DNA vaccines expressing either gp120-mC3d 3 or sCD4-gp120-mC3d 3 elicited antibodies that neutralized homologous virus infection. However, the use of sCD4-gp120-mC3d 3 -DNA elicited the highest titers of neutralizing antibodies that persisted after depletion of anti-hCD4 antibodies. Interestingly, only mice vaccinated with DNA expressing sCD4-gp120-mC3d 3 had antibodies that elicited cross-protective neutralizing antibodies. The fusion of sCD4 to the HIV-1 envelope exposes neutralizing epitopes that elicit broad protective immunity when the fusion complex is coupled with the molecular adjuvant, C3d

Challenges in HIV vaccine research for treatment and prevention

Directory of Open Access Journals (Sweden)

Barbara eEnsoli

2014-09-01

Full Text Available Many attempts have been made or are ongoing for HIV prevention and HIV cure. Many successes are in the list, particularly for HIV drugs, recently proposed also for prevention. However, no eradication of infection has been achieved so far with any drug.Further, a residual immune dysregulation associated to chronic immune activation and incomplete restoration of B and T cell subsets, together with HIV DNA persistence in reservoirs, are still unmet needs of the highly active antiretroviral therapy (HAART, causing novel non-AIDS related diseases that account for a higher risk of death even in virologically suppressed patients. These ART unmet needs represent a problem, which is expected to increase by ART roll out. Further, in countries such as South Africa, where 6 millions of individuals are infected, ART appears unable to contain the epidemics. Regretfully, all the attempts at developing a preventative vaccine have been largely disappointing. However, recent therapeutic immunization strategies have opened new avenues for HIV treatment, which might be exploitable also for preventative vaccine approaches. For example, immunization strategies aimed at targeting key viral products responsible of virus transmission, activation and maintenance of virus reservoirs may intensify drug efficacy and lead to a functional cure providing new perspectives also for prevention and future virus eradication strategies. However, this approach imposes new challenges to the scientific community, vaccine developers and regulatory bodies, such as the identification of novel immunological and virological biomarkers to assess efficacy endpoints, taking advantage from the natural history of infection and exploiting lessons from former trials.This review will focus first on recent advancement of therapeutic strategies, then on the progresses made in preventative approaches, discussing concepts and problems for the way ahead for the development of vaccines for HIV treatment

Population-level effect of potential HSV2 prophylactic vaccines on HIV incidence in sub-Saharan Africa

Science.gov (United States)

Freeman, Esther E.; White, Richard G.; Bakker, Roel; Orroth, Kate K.; Weiss, Helen A.; Buvé, Anne; Hayes, Richard J.; Glynn, Judith R.

2009-01-01

Herpes simplex virus type-2 (HSV2) infection increases HIV transmission. We explore the impact of a potential prophylactic HSV2 vaccination on HIV incidence in Africa using STDSIM an individual-based model. A campaign that achieved 70% coverage over 5 years with a vaccine that reduced susceptibility to HSV2 acquisition and HSV2 reactivation by 75% for 10 years, reduced HIV incidence by 30–40% after 20 years (range 4–66%). Over 20 years, in most scenarios fewer than 100 vaccinations were required to avert one HIV infection. HSV2 vaccines could have a substantial impact on HIV incidence. Intensified efforts are needed to develop an effective HSV2 vaccine. PMID:19071187

HIV-1–Infected Individuals in Antiretroviral Therapy React Specifically With Polyfunctional T-Cell Responses to Gag p24

DEFF Research Database (Denmark)

Brandt, Lea; Benfield, Thomas; Kronborg, Gitte

2013-01-01

Still no effective HIV-1 prophylactic or therapeutic vaccines are available. However, as the proportion of HIV-1-infected individuals on antiretroviral treatment is increasing, knowledge about the residual immune response is important for the possible development of an HIV-1 vaccine.......Still no effective HIV-1 prophylactic or therapeutic vaccines are available. However, as the proportion of HIV-1-infected individuals on antiretroviral treatment is increasing, knowledge about the residual immune response is important for the possible development of an HIV-1 vaccine....

A phase I double blind, placebo-controlled, randomized study of a multigenic HIV-1 adenovirus subtype 35 vector vaccine in healthy uninfected adults.

Directory of Open Access Journals (Sweden)

Michael C Keefer

Full Text Available We conducted a phase I, randomized, double-blind, placebo-controlled trial to assess the safety and immunogenicity of escalating doses of two recombinant replication defective adenovirus serotype 35 (Ad35 vectors containing gag, reverse transcriptase, integrase and nef (Ad35-GRIN and env (Ad35-ENV, both derived from HIV-1 subtype A isolates. The trial enrolled 56 healthy HIV-uninfected adults.Ad35-GRIN/ENV (Ad35-GRIN and Ad35-ENV mixed in the same vial in equal proportions or Ad35-GRIN was administered intramuscularly at 0 and 6 months. Participants were randomized to receive either vaccine or placebo (10/4 per group, respectively within one of four dosage groups: Ad35-GRIN/ENV 2×10(9 (A, 2×10(10 (B, 2×10(11 (C, or Ad35-GRIN 1×10(10 (D viral particles.No vaccine-related serious adverse event was reported. Reactogenicity events reported were dose-dependent, mostly mild or moderate, some severe in Group C volunteers, all transient and resolving spontaneously. IFN-γ ELISPOT responses to any vaccine antigen were detected in 50, 56, 70 and 90% after the first vaccination, and in 75, 100, 88 and 86% of Groups A-D vaccine recipients after the second vaccination, respectively. The median spot forming cells (SFC per 10(6 PBMC to any antigen was 78-139 across Groups A-C and 158-174 in Group D, after each of the vaccinations with a maximum of 2991 SFC. Four to five HIV proteins were commonly recognized across all the groups and over multiple timepoints. CD4+ and CD8+ T-cell responses were polyfunctional. Env antibodies were detected in all Group A-C vaccinees and Gag antibodies in most vaccinees after the second immunization. Ad35 neutralizing titers remained low after the second vaccination.Ad35-GRIN/ENV reactogenicity was dose-related. HIV-specific cellular and humoral responses were seen in the majority of volunteers immunized with Ad35-GRIN/ENV or Ad35-GRIN and increased after the second vaccination. T-cell responses were broad and polyfunctional

Motivations to participate in a Phase I/II HIV vaccine trial: A descriptive study from Dar es Salaam, Tanzania

Directory of Open Access Journals (Sweden)

E. A. M. Tarimo

2016-02-01

Full Text Available Abstract Background The search for an efficacious HIV vaccine is a global priority. To date only one HIV vaccine trial (RV144 has shown modest efficacy in a phase III trial. With existing different HIV-1 subtypes and frequent mutations, multiple trials are needed from different geographical sites particularly in sub-Saharan Africa where most HIV infections occur. Thus, motivations to participate in HIV vaccine trials among Tanzanians need to be assessed. This paper describes the motives of Police Officers who showed great interest to volunteer in HIVIS-03 in Dar es Salaam, Tanzania. Methods A descriptive cross-sectional study was conducted among Police Officers who showed interest to participate in the HIVIS-03, a phase I/II HIV vaccine trial in Dar es Salaam. Prior to detailed training sessions about HIV vaccine trials, the potential participants narrated their individual motives to participate in the trial on a piece of paper. Descriptive analysis using content approach and frequency distributions were performed. Results Of the 265 respondents, 242 (91.3 % provided their socio-demographic characteristics as well as reasons that would make them take part in the proposed trial. Majority, (39.7 %, cited altruism as the main motive. Women were more likely to volunteer due to altruism compared to men (P < 0.01. Researchers’ explanations about HIV/AIDS vaccine studies motivated 15.3 %. More men (19.6 % than women (1.7 % were motivated to volunteer due to researchers’ explanations (P < 0.001. Also, compared to other groups, those unmarried and educated up to secondary level of education were motivated to volunteer due to researchers’ explanation (P < 0.05. Other reasons were: desire to become a role model (18.6 %; to get knowledge for educating others (14.0 %; to cooperate with researchers in developing an HIV vaccine (9.5 %; to get protection against HIV infection (7.0 %, and severity of the disease within families (6.2�

Pregnancy incidence and correlates during the HVTN 503 Phambili HIV vaccine trial conducted among South African women.

Directory of Open Access Journals (Sweden)

Mary H Latka

Full Text Available HIV prevention trials are increasingly being conducted in sub-Saharan Africa. Women at risk for HIV are also at risk of pregnancy. To maximize safety, women agree to avoid pregnancy during trials, yet pregnancies occur. Using data from the HVTN 503/"Phambili" vaccine trial, we report pregnancy incidence during and after the vaccination period and identify factors, measured at screening, associated with incident pregnancy.To enrol in the trial, women agreed and were supported to avoid pregnancy until 1 month after their third and final vaccination ("vaccination period", corresponding to the first 7 months of follow-up. Unsterilized women, pooled across study arms, were analyzed. Poisson regression compared pregnancy rates during and after the vaccination period. Cox proportional hazards regression identified associations with first pregnancy.Among 352 women (median age 23 yrs; median follow-up 1.5 yrs, pregnancy incidence was 9.6/100 women-years overall and 6.8/100 w-yrs and 11.3/100 w-yrs during and after the vaccination period, respectively [Rate Ratio = 0.60 (0.32-1.14, p = 0.10]. In multivariable analysis, pregnancy was reduced among women who: enrolled at sites providing contraception on-site [HR = 0.43, 95% CI (0.22-0.86]; entered the trial as injectable contraceptive users [HR = 0.37 (0.21-0.67] or as consistent condom users (trend [HR = 0.54 (0.28-1.04]. Compared with women with a single partner of HIV-unknown status, pregnancy rates were increased among women with: a single partner whose status was HIV-negative [HR = 2.34(1.16-4.73] and; 2 partners both of HIV-unknown status [HR = 4.42(1.59-12.29]. Women with 2 more of these risk factors: marijuana use, heavy drinking, or use of either during sex, had increased pregnancy incidence [HR = 2.66 (1.24-5.72].It is possible to screen South African women for pregnancy risk at trial entry. Providing injectable contraception for free on-site and supporting consistent condom use may reduce

Maturation Pathways of Cross-Reactive HIV-1 Neutralizing Antibodies

Directory of Open Access Journals (Sweden)

Dimiter S. Dimitrov

2009-11-01

Full Text Available Several human monoclonal antibodies (hmAbs and antibody fragments, including the best characterized in terms of structure-function b12 and Fab X5, exhibit relatively potent and broad HIV-1 neutralizing activity. However, the elicitation of b12 or b12-like antibodies in vivo by vaccine immunogens based on the HIV-1 envelope glycoprotein (Env has not been successful. B12 is highly divergent from the closest corresponding germline antibody while X5 is less divergent. We have hypothesized that the relatively high degree of specific somatic hypermutations may preclude binding of the HIV-1 envelope glycoprotein (Env to closest germline antibodies, and that identifying antibodies that are intermediates in the pathways to maturation could help design novel vaccine immunogens to guide the immune system for their enhanced elicitation. In support of this hypothesis we have previously found that a germline-like b12 (monovalent and bivalent scFv as an Fc fusion protein or IgG lacks measurable binding to an Env as measured by ELISA with a sensitivity in the μM range [1]; here we present evidence confirming and expanding these findings for a panel of Envs. In contrast, a germline-like scFv X5 bound Env with high (nM affinity. To begin to explore the maturation pathways of these antibodies we identified several possible b12 intermediate antibodies and tested their neutralizing activity. These intermediate antibodies neutralized only some HIV-1 isolates and with relatively weak potency. In contrast, germline-like scFv X5 neutralized a subset of the tested HIV-1 isolates with comparable efficiencies to that of the mature X5. These results could help explain the relatively high immunogenicity of the coreceptor binding site on gp120 and the abundance of CD4-induced (CD4i antibodies in HIV-1-infected patients (X5 is a CD4i antibody as well as the maturation pathway of X5. They also can help identify antigens that can bind specifically to b12 germline and

Biochemistry and biophysics of HIV-1 gp41 - membrane interactions and implications for HIV-1 envelope protein mediated viral-cell fusion and fusion inhibitor design.

Science.gov (United States)

Cai, Lifeng; Gochin, Miriam; Liu, Keliang

2011-12-01

Human immunodeficiency virus type 1 (HIV-1), the pathogen of acquired immunodeficiency syndrome (AIDS), causes ~2 millions death every year and still defies an effective vaccine. HIV-1 infects host cells through envelope protein - mediated virus-cell fusion. The transmembrane subunit of envelope protein, gp41, is the molecular machinery which facilitates fusion. Its ectodomain contains several distinguishing functional domains, fusion peptide (FP), Nterminal heptad repeat (NHR), C-terminal heptad repeat (CHR) and membrane proximal extracellular region (MPER). During the fusion process, FP inserts into the host cell membrane, and an extended gp41 prehairpin conformation bridges the viral and cell membranes through MPER and FP respectively. Subsequent conformational change of the unstable prehairpin results in a coiled-coil 6-helix bundle (6HB) structure formed between NHR and CHR. The energetics of 6HB formation drives membrane apposition and fusion. Drugs targeting gp41 functional domains to prevent 6HB formation inhibit HIV-1 infection. T20 (enfuvirtide, Fuzeon) was approved by the US FDA in 2003 as the first fusion inhibitor. It is a 36-residue peptide from the gp41 CHR, and it inhibits 6HB formation by targeting NHR and lipids. Development of new fusion inhibitors, especially small molecule drugs, is encouraged to overcome the shortcomings of T20 as a peptide drug. Hydrophobic characteristics and membrane association are critical for gp41 function and mechanism of action. Research in gp41-membrane interactions, using peptides corresponding to specific functional domains, or constructs including several interactive domains, are reviewed here to get a better understanding of gp41 mediated virus-cell fusion that can inform or guide the design of new HIV-1 fusion inhibitors.

Effect of race/ethnicity on participation in HIV vaccine trials and comparison to other trials of biomedical prevention.

Science.gov (United States)

Dhalla, Shayesta; Poole, Gary

2014-01-01

Racial/ethnic minorities are underrepresented in actual HIV vaccine trials in North America, and willingness to participate (WTP) and retention in an HIV vaccine trial may differ from that in Whites. In this review, the authors identified HIV vaccine preparedness studies (VPS) in North America in high-risk populations that examined the relationship between race/ethnicity and WTP in a preventive phase 3 HIV vaccine trial, and the relationship to retention. Studies were categorized by risk group, and comparison group (Whites vs. non-Whites). Other types of trials of biomedical prevention were also identified, and WTP and retention rates were compared and contrasted to actual HIV vaccine trials. In the studies identified, WTP in a hypothetical trial HIV vaccine trial did not differ by race/ethnicity. In contrast, actual HIV vaccine trials, an HIV acquisition trial, and a phase 2B preexposure prophylaxis (PrEP) trial have enrolled a large percentage of White men. Human papilloma virus (HPV) privately-funded trials have also enrolled a large number of Whites, due to convenience sampling. Retention in the HIV acquisition trial was lower in African-Americans compared with Whites. Strategies to increase WTP and enhanced retention (ER) strategies may help in recruiting and retaining minority participants in actual HIV vaccine trials and other trials of biomedical prevention.

Engineering and Characterization of a Fluorescent Native-Like HIV-1 Envelope Glycoprotein Trimer

Directory of Open Access Journals (Sweden)

Kwinten Sliepen

2015-10-01

Full Text Available Generation of a stable, soluble mimic of the HIV-1 envelope glycoprotein (Env trimer on the virion surface has been considered an important first step for developing a successful HIV-1 vaccine. Recently, a soluble native-like Env trimer (BG505 SOSIP.664 has been described. This protein has facilitated major advances in the HIV-1 vaccine field, since it was the first Env immunogen that induced consistent neutralizing antibodies against a neutralization-resistant (tier 2 virus. Moreover, BG505 SOSIP.664 enabled elucidation of the atomic resolution structure of the Env trimer and facilitated the isolation and characterization of new broadly neutralizing antibodies against HIV-1. Here, we designed and characterized the BG505 SOSIP.664 trimer fused to fluorescent superfolder GFP (sfGFP, a GFP variant that allows efficient folding (BG505 SOSIP.664-sfGFP. Despite the presence of the sfGFP, the Env protein largely retained its morphology, antigenicity, glycan composition, and thermostability. In addition, we show that BG505 SOSIP.664-sfGFP can be used for fluorescence-based assays, such as flow cytometry.

A vaccine encoding conserved promiscuous HIV CD4 epitopes induces broad T cell responses in mice transgenic to multiple common HLA class II molecules.

Directory of Open Access Journals (Sweden)

Susan Pereira Ribeiro

Full Text Available Current HIV vaccine approaches are focused on immunogens encoding whole HIV antigenic proteins that mainly elicit cytotoxic CD8+ responses. Mounting evidence points toward a critical role for CD4+ T cells in the control of immunodeficiency virus replication, probably due to cognate help. Vaccine-induced CD4+ T cell responses might, therefore, have a protective effect in HIV replication. In addition, successful vaccines may have to elicit responses to multiple epitopes in a high proportion of vaccinees, to match the highly variable circulating strains of HIV. Using rational vaccine design, we developed a DNA vaccine encoding 18 algorithm-selected conserved, "promiscuous" (multiple HLA-DR-binding B-subtype HIV CD4 epitopes - previously found to be frequently recognized by HIV-infected patients. We assessed the ability of the vaccine to induce broad T cell responses in the context of multiple HLA class II molecules using different strains of HLA class II- transgenic mice (-DR2, -DR4, -DQ6 and -DQ8. Mice displayed CD4+ and CD8+ T cell responses of significant breadth and magnitude, and 16 out of the 18 encoded epitopes were recognized. By virtue of inducing broad responses against conserved CD4+ T cell epitopes that can be recognized in the context of widely diverse, common HLA class II alleles, this vaccine concept may cope both with HIV genetic variability and increased population coverage. The vaccine may thus be a source of cognate help for HIV-specific CD8+ T cells elicited by conventional immunogens, in a wide proportion of vaccinees.

Theory-Based Analysis of Interest in an HIV Vaccine for Reasons Indicative of Risk Compensation Among African American Women.

Science.gov (United States)

Painter, Julia E; Temple, Brandie S; Woods, Laura A; Cwiak, Carrie; Haddad, Lisa B; Mulligan, Mark J; DiClemente, Ralph J

2018-06-01

Licensure of an HIV vaccine could reduce or eliminate HIV among vulnerable populations. However, vaccine effectiveness could be undermined by risk compensation (RC), defined by an increase in risky behavior due to a belief that the vaccine will confer protection. Interest in an HIV vaccine for reasons indicative of RC may serve as an indicator of actual RC in a postlicensure era. This study assessed factors associated with interest in an HIV vaccine for reasons indicative of RC among African American women aged 18 to 55 years, recruited from a hospital-based family planning clinic in Atlanta, Georgia ( N = 321). Data were collected using audio-computer-assisted surveys. Survey items were guided by risk homeostasis theory and social cognitive theory. Multivariable logistic regression was used to assess determinants of interest in an HIV vaccine for reasons indicative of RC. Thirty-eight percent of the sample expressed interest in an HIV vaccine for at least one reason indicative of RC. In the final model, interest in an HIV vaccine for reasons indicative of RC was positively associated with higher impulsivity, perceived benefits of sexual risk behaviors, and perceived benefits of HIV vaccination; it was negatively associated with having at least some college education, positive future orientation, and self-efficacy for sex refusal. Results suggest that demographic, personality, and theory-based psychosocial factors are salient to wanting an HIV vaccine for reasons indicative of RC, and underscore the need for risk-reduction counseling alongside vaccination during the eventual rollout of an HIV vaccine.

Broad and potent immune responses to a low dose intradermal HIV-1 DNA boosted with HIV-1 recombinant MVA among healthy adults in Tanzania☆,☆☆

Science.gov (United States)

Bakari, Muhammad; Aboud, Said; Nilsson, Charlotta; Francis, Joel; Buma, Deus; Moshiro, Candida; Aris, Eric A.; Lyamuya, Eligius F.; Janabi, Mohamed; Godoy-Ramirez, Karina; Joachim, Agricola; Polonis, Victoria R.; Bråve, Andreas; Earl, Patricia; Robb, Merlin; Marovich, Mary; Wahren, Britta; Pallangyo, Kisali; Biberfeld, Gunnel; Mhalu, Fred; Sandström, Eric

2016-01-01

Background We conducted a phase I/II randomized placebo-controlled trial with the aim of exploring whether priming with a low intradermal dose of a multiclade, multigene HIV-1 DNA vaccine could improve the immunogenicity of the same vaccine given intramuscularly prior to boosting with a heterologous HIV-1 MVA among healthy adults in Dar es Salaam, Tanzania. Methods Sixty HIV-uninfected volunteers were randomized to receive DNA plasmid vaccine 1 mg intradermally (id), n = 20, or 3.8 mg intramuscularly (im), n = 20, or placebo, n = 20, using a needle-free injection device. DNA plasmids encoding HIV-1 genes gp160 subtype A, B, C; rev B; p17/p24 gag A, B and Rtmut B were given at weeks 0, 4 and 12. Recombinant MVA (108 pfu) expressing HIV-1 Env, Gag, Pol of CRF01_AE or placebo was administered im at month 9 and 21. Results The vaccines were well tolerated. Two weeks after the third HIV-DNA injection, 22/38 (58%) vaccinees had IFN-γ ELISpot responses to Gag. Two weeks after the first HIV-MVA boost all 35 (100%) vaccinees responded to Gag and 31 (89%) to Env. Two to four weeks after the second HIV-MVA boost, 28/29 (97%) vaccinees had IFN-γ ELISpot responses, 27 (93%) to Gag and 23 (79%) to Env. The id-primed recipients had significantly higher responses to Env than im recipients. Intracellular cytokine staining for Gag-specific IFN-γ/IL-2 production showed both CD8+ and CD4+ T cell responses. All vaccinees had HIV-specific lymphoproliferative responses. All vaccinees reacted in diagnostic HIV serological tests and 26/29 (90%) had antibodies against gp160 after the second HIV-MVA boost. Furthermore, while all of 29 vaccinee sera were negative for neutralizing antibodies against clade B, C and CRF01 AE pseudoviruses in the TZM-bl neutralization assay, in a PBMC assay, the response rate ranged from 31% to 83% positives, depending upon the clade B or CRF01_AE virus tested. This vaccine approach is safe and highly immunogenic. Low dose, id HIV-DNA priming elicited higher

Immunogenicity and Safety of the 13-Valent Pneumococcal Conjugate Vaccine versus the 23-Valent Polysaccharide Vaccine in Unvaccinated HIV-Infected Adults: A Pilot, Prospective Controlled Study.

Directory of Open Access Journals (Sweden)

Francesca Lombardi

Full Text Available Definition of the optimal pneumococcal vaccine strategy in HIV-infected adults is still under evaluation. We aimed to compare immunogenicity and safety of the 13-valent pneumococcal conjugate vaccine (PCV13 versus the 23-valent polysaccharide vaccine (PPSV23 in HIV-infected adults.We performed a pilot, prospective controlled study enrolling HIV-infected pneumococcal vaccine-naïve outpatients, aged 18-65 years with CD4 counts ≥200 cells/μL. Eligible subjects were recruited into two parallel groups: group 1 (n = 50 received two doses of PCV13 eight weeks apart, and group 2 (n = 50 received one dose of PPSV23, as part of their standard of care. Anti-pneumococcal capsular polysaccharide immunoglobulin G concentrations were quantified by ELISA at baseline, 8, 24 and 48 weeks. Clinical and viro-immunological follow-up was performed at the same time points. Unvaccinated, age-matched HIV-negative adults (n = 100 were also enrolled as baseline controls.Pre-vaccination specific IgG titers for each pneumococcal antigen did not differ between study groups but they were constantly lower than those from the HIV-negative controls. After immunization, significant increases in IgG titers were observed in both study groups at each time point compared to baseline, but response to serotype 3 was blunted in group 1. Antibody titers for each antigen did not differ between study groups at week 48. Overall, the proportion of subjects achieving seroprotection and seroconversion to all serotypes was comparable between groups. A marked decrease in IgG levels over time was observed with both vaccines. No relevant adverse reactions were reported in either group.In this population with favorable immune profile, no relevant differences were observed in immunogenicity between PCV13 and PPSV23. Both vaccines were safe and well tolerated.ClinicalTrials.gov NCT02123433.

Immunization with Clinical HIV-1 Env Proteins Induces Broad Antibody Dependent Cellular Cytotoxicity-Mediating Antibodies in a Rabbit Vaccination Model

DEFF Research Database (Denmark)

Karlsson, Ingrid; Borggren, Marie; Jensen, Sanne Skov

2018-01-01

The induction of both neutralizing antibodies and non-neutralizing antibodies with effector functions, for example, antibody-dependent cellular cytotoxicity (ADCC), is desired in the search for effective vaccines against HIV-1. In the pursuit of novel immunogens capable of inducing an efficient a...

Glycosylation in HIV-1 envelope glycoprotein and its biological implications

KAUST Repository

Ho, Yung Shwen

2013-08-01

Glycosylation of HIV-1 envelope proteins (Env gp120/gp41) plays a vital role in viral evasion from the host immune response, which occurs through the masking of key neutralization epitopes and the presentation of the Env glycosylation as \\'self\\' to the host immune system. Env glycosylation is generally conserved, yet its continual evolution plays an important role in modulating viral infectivity and Env immunogenicity. Thus, it is believed that Env glycosylation, which is a vital part of the HIV-1 architecture, also controls intra- and inter-clade genetic variations. Discerning intra- and inter-clade glycosylation variations could therefore yield important information for understanding the molecular and biological differences between HIV clades and may assist in effectively designing Env-based immunogens and in clearly understanding HIV vaccines. This review provides an in-depth perspective of various aspects of Env glycosylation in the context of HIV-1 pathogenesis. © 2013 Future Medicine Ltd.

Serum neutralizing activities from a Beijing homosexual male cohort infected with different subtypes of HIV-1 in China.

Directory of Open Access Journals (Sweden)

Mingshun Zhang

Full Text Available Protective antibodies play a critical role in an effective HIV vaccine; however, eliciting antibodies to block infection by viruses from diverse genetic subtypes remains a major challenge. As the world's most populous country, China has been under the threat of at least three major subtypes of circulating HIV-1 viruses. Understanding the cross reactivity and specificities of serum antibody responses that mediate broad neutralization of the virus in HIV-1 infected Chinese patients will provide valuable information for the design of vaccines to prevent HIV-1 transmission in China. Sera from a cohort of homosexual men, who have been managed by a major HIV clinical center in Beijing, China, were analyzed for cross-sectional neutralizing activities against pseudotyped viruses expressing Env antigens of the major subtype viruses (AE, BC and B subtypes circulating in China. Neutralizing activities in infected patients' blood were most capable of neutralizing viruses in the homologous subtype; however, a subset of blood samples was able to achieve broad neutralizing activities across different subtypes. Such cross neutralizing activity took 1-2 years to develop and CD4 binding site antibodies were critical components in these blood samples. Our study confirmed the presence of broadly neutralizing sera in China's HIV-1 patient population. Understanding the specificity and breadth of these neutralizing activities can guide efforts for the development of HIV vaccines against major HIV-1 viruses in China.

Pregnancy Incidence and Correlates during the HVTN 503 Phambili HIV Vaccine Trial Conducted among South African Women

Science.gov (United States)

Latka, Mary H.; Fielding, Katherine; Gray, Glenda E.; Bekker, Linda-Gail; Nchabeleng, Maphoshane; Mlisana, Koleka; Nielson, Tanya; Roux, Surita; Mkhize, Baningi; Mathebula, Matsontso; Naicker, Nivashnee; de Bruyn, Guy; Kublin, James; Churchyard, Gavin J.

2012-01-01

Background HIV prevention trials are increasingly being conducted in sub-Saharan Africa. Women at risk for HIV are also at risk of pregnancy. To maximize safety, women agree to avoid pregnancy during trials, yet pregnancies occur. Using data from the HVTN 503/“Phambili” vaccine trial, we report pregnancy incidence during and after the vaccination period and identify factors, measured at screening, associated with incident pregnancy. Methods To enrol in the trial, women agreed and were supported to avoid pregnancy until 1 month after their third and final vaccination (“vaccination period”), corresponding to the first 7 months of follow-up. Unsterilized women, pooled across study arms, were analyzed. Poisson regression compared pregnancy rates during and after the vaccination period. Cox proportional hazards regression identified associations with first pregnancy. Results Among 352 women (median age 23 yrs; median follow-up 1.5 yrs), pregnancy incidence was 9.6/100 women-years overall and 6.8/100 w-yrs and 11.3/100 w-yrs during and after the vaccination period, respectively [Rate Ratio = 0.60 (0.32–1.14), p = 0.10]. In multivariable analysis, pregnancy was reduced among women who: enrolled at sites providing contraception on-site [HR = 0.43, 95% CI (0.22–0.86)]; entered the trial as injectable contraceptive users [HR = 0.37 (0.21–0.67)] or as consistent condom users (trend) [HR = 0.54 (0.28–1.04)]. Compared with women with a single partner of HIV-unknown status, pregnancy rates were increased among women with: a single partner whose status was HIV-negative [HR = 2.34(1.16–4.73)] and; 2 partners both of HIV-unknown status [HR = 4.42(1.59–12.29)]. Women with 2 more of these risk factors: marijuana use, heavy drinking, or use of either during sex, had increased pregnancy incidence [HR = 2.66 (1.24–5.72)]. Conclusions It is possible to screen South African women for pregnancy risk at trial entry. Providing injectable

South African Research Ethics Committee Review of Standards of Prevention in HIV Vaccine Trial Protocols.

Science.gov (United States)

Essack, Zaynab; Wassenaar, Douglas R

2018-04-01

HIV prevention trials provide a prevention package to participants to help prevent HIV acquisition. As new prevention methods are proven effective, this raises ethical and scientific design complexities regarding the prevention package or standard of prevention. Given its high HIV incidence and prevalence, South Africa has become a hub for HIV prevention research. For this reason, it is critical to study the implementation of relevant ethical-legal frameworks for such research in South Africa. This qualitative study used in-depth interviews to explore the practices and perspectives of eight members of South African research ethics committees (RECs) who have reviewed protocols for HIV vaccine trials. Their practices and perspectives are compared with ethics guideline requirements for standards of prevention.

Loss of long term protection with the inclusion of HIV pol to a DNA vaccine encoding gag.

Science.gov (United States)

Garrod, Tamsin J; Gargett, Tessa; Yu, Wenbo; Major, Lee; Burrell, Christopher J; Wesselingh, Steven; Suhrbier, Andreas; Grubor-Bauk, Branka; Gowans, Eric J

2014-11-04

Traditional vaccine strategies that induce antibody responses have failed to protect against HIV infection in clinical trials, and thus cell-mediated immunity is now an additional criterion. Recent clinical trials that aimed to induce strong T cell responses failed to do so. Therefore, to enhance induction of protective T cell responses, it is crucial that the optimum antigen combination is chosen. Limited research has been performed into the number of antigens selected for an HIV vaccine. This study aimed to compare DNA vaccines encoding either a single HIV antigen or a combination of two antigens, using intradermal vaccination of C57BL/6 mice. Immune assays were performed on splenocytes, and in vivo protection was examined by challenge with a chimeric virus, EcoHIV, able to infect mouse but not human leukocytes, at 10 days (short term) and 60 days (long term) post final vaccination. At 60 days there was significantly lower frequency of induced antigen-specific CD8(+) T cells in the spleens of pCMVgag-pol-vaccinated mice compared with mice which received pCMVgag only. Most importantly, short term viral control of EcoHIV was similar for pCMVgag and pCMVgag-pol-vaccinated mice at day 10, but only the pCMVgag-vaccinated significantly controlled EcoHIV at day 60 compared with pCMV-vaccinated mice, showing that control was reduced with the inclusion of the HIV pol gene. Copyright © 2014 Elsevier B.V. All rights reserved.

Monoclonal Antibodies, Derived from Humans Vaccinated with the RV144 HIV Vaccine Containing the HVEM Binding Domain of Herpes Simplex Virus (HSV) Glycoprotein D, Neutralize HSV Infection, Mediate Antibody-Dependent Cellular Cytotoxicity, and Protect Mice from Ocular Challenge with HSV-1.

Science.gov (United States)

Wang, Kening; Tomaras, Georgia D; Jegaskanda, Sinthujan; Moody, M Anthony; Liao, Hua-Xin; Goodman, Kyle N; Berman, Phillip W; Rerks-Ngarm, Supachai; Pitisuttithum, Punnee; Nitayapan, Sorachai; Kaewkungwal, Jaranit; Haynes, Barton F; Cohen, Jeffrey I

2017-10-01

The RV144 HIV vaccine trial included a recombinant HIV glycoprotein 120 (gp120) construct fused to a small portion of herpes simplex virus 1 (HSV-1) glycoprotein D (gD) so that the first 40 amino acids of gp120 were replaced by the signal sequence and the first 27 amino acids of the mature form of gD. This region of gD contains most of the binding site for HVEM, an HSV receptor important for virus infection of epithelial cells and lymphocytes. RV144 induced antibodies to HIV that were partially protective against infection, as well as antibodies to HSV. We derived monoclonal antibodies (MAbs) from peripheral blood B cells of recipients of the RV144 HIV vaccine and showed that these antibodies neutralized HSV-1 infection in cells expressing HVEM, but not the other major virus receptor, nectin-1. The MAbs mediated antibody-dependent cellular cytotoxicity (ADCC), and mice that received the MAbs and were then challenged by corneal inoculation with HSV-1 had reduced eye disease, shedding, and latent infection. To our knowledge, this is the first description of MAbs derived from human recipients of a vaccine that specifically target the HVEM binding site of gD. In summary, we found that monoclonal antibodies derived from humans vaccinated with the HVEM binding domain of HSV-1 gD (i) neutralized HSV-1 infection in a cell receptor-specific manner, (ii) mediated ADCC, and (iii) reduced ocular disease in virus-infected mice. IMPORTANCE Herpes simplex virus 1 (HSV-1) causes cold sores and neonatal herpes and is a leading cause of blindness. Despite many trials, no HSV vaccine has been approved. Nectin-1 and HVEM are the two major cellular receptors for HSV. These receptors are expressed at different levels in various tissues, and the role of each receptor in HSV pathogenesis is not well understood. We derived human monoclonal antibodies from persons who received the HIV RV144 vaccine that contained the HVEM binding domain of HSV-1 gD fused to HIV gp120. These antibodies were

Executive summary and recommendations from WHO/UNAIDS and AAVP consultation on: 'The inclusion of adolescents in HIV vaccine trials', 16-18 March 2006 in Gaborone, Botswana.

Science.gov (United States)

Osmanov, Saladin

2007-09-12

This report summarizes the discussions and recommendations from a consultation held in Gaborone, Botswana (16-19 March 2006), organized by the joint World Health Organization (WHO)/United Nations Programme on HIV/AIDS (UNAIDS) HIV Vaccine Initiative (HVI) and the African AIDS Vaccine Programme (AAVP). The consultation considered key challenges and strategies in enrolling adolescents into HIV vaccine clinical trials, relevant to developing countries, in particular in eastern and southern Africa. Approaches were identified that might address and resolve country-specific challenges related to scientific, legal, ethical, regulatory and community aspects of the involvement of adolescents in HIV vaccine trials. This executive summary is formulated for a broader dissemination of the outcomes of the meeting to the general clinical, scientific and regulatory community involved in the review, approval and monitoring of clinical trials and potential licensing of HIV vaccine candidates. Four major topics were discussed and recommendations developed with regard to: (i) criteria for products selection and clinical trial design; (ii) ethical and legal issues; (iii) community acceptance and participation; and (iv) regulatory considerations. The recommendations of this meeting were further discussed and endorsed by the WHO/UNAIDS HIV Vaccine Advisory Committee.

Superior induction of T cell responses to conserved HIV-1 regions by electroporated alphavirus replicon DNA compared to that with conventional plasmid DNA vaccine.

Science.gov (United States)

Knudsen, Maria L; Mbewe-Mvula, Alice; Rosario, Maximillian; Johansson, Daniel X; Kakoulidou, Maria; Bridgeman, Anne; Reyes-Sandoval, Arturo; Nicosia, Alfredo; Ljungberg, Karl; Hanke, Tomás; Liljeström, Peter

2012-04-01

Vaccination using "naked" DNA is a highly attractive strategy for induction of pathogen-specific immune responses; however, it has been only weakly immunogenic in humans. Previously, we constructed DNA-launched Semliki Forest virus replicons (DREP), which stimulate pattern recognition receptors and induce augmented immune responses. Also, in vivo electroporation was shown to enhance immune responses induced by conventional DNA vaccines. Here, we combine these two approaches and show that in vivo electroporation increases CD8(+) T cell responses induced by DREP and consequently decreases the DNA dose required to induce a response. The vaccines used in this study encode the multiclade HIV-1 T cell immunogen HIVconsv, which is currently being evaluated in clinical trials. Using intradermal delivery followed by electroporation, the DREP.HIVconsv DNA dose could be reduced to as low as 3.2 ng to elicit frequencies of HIV-1-specific CD8(+) T cells comparable to those induced by 1 μg of a conventional pTH.HIVconsv DNA vaccine, representing a 625-fold molar reduction in dose. Responses induced by both DREP.HIVconsv and pTH.HIVconsv were further increased by heterologous vaccine boosts employing modified vaccinia virus Ankara MVA.HIVconsv and attenuated chimpanzee adenovirus ChAdV63.HIVconsv. Using the same HIVconsv vaccines, the mouse observations were supported by an at least 20-fold-lower dose of DNA vaccine in rhesus macaques. These data point toward a strategy for overcoming the low immunogenicity of DNA vaccines in humans and strongly support further development of the DREP vaccine platform for clinical evaluation.

Safety and immunogenicity of RTS,S/AS01 malaria vaccine in infants and children with WHO stage 1 or 2 HIV disease: a randomised, double-blind, controlled trial.

Science.gov (United States)

Otieno, Lucas; Oneko, Martina; Otieno, Walter; Abuodha, Joseph; Owino, Emmanuel; Odero, Chris; Mendoza, Yolanda Guerra; Andagalu, Ben; Awino, Norbert; Ivinson, Karen; Heerwegh, Dirk; Otsyula, Nekoye; Oziemkowska, Maria; Usuf, Effua Abigail; Otieno, Allan; Otieno, Kephas; Leboulleux, Didier; Leach, Amanda; Oyieko, Janet; Slutsker, Laurence; Lievens, Marc; Cowden, Jessica; Lapierre, Didier; Kariuki, Simon; Ogutu, Bernhards; Vekemans, Johan; Hamel, Mary J

2016-10-01

Malaria remains a major global public health concern, especially in sub-Saharan Africa. The RTS,S/AS01 malaria candidate vaccine was reviewed by the European Medicines Agency and received a positive scientific opinion; WHO subsequently recommended pilot implementation in sub-Saharan African countries. Because malaria and HIV overlap geographically, HIV-infected children should be considered for RTS,S/AS01 vaccination. We therefore aimed to assess the safety of RTS,S/AS01 in HIV-infected children at two sites in western Kenya. We did a randomised, double-blind, controlled trial at the clinical trial sites of the Kenya Medical Research Institute (KEMRI)-Walter Reed Army Institute of research in Kisumu and the KEMRI/US Centers for Disease Control and Prevention in Siaya. Eligible participants were infants and children aged from 6 weeks to 17 months with WHO stage 1 or 2 HIV disease (documented positive by DNA PCR), whether or not they were receiving antiretroviral therapy (ART). We randomly assigned participants (1:1) to receive three doses of either RTS,S/AS01 or rabies vaccine (both 0·5 mL per dose by intramuscular injection), given once per month at 0, 1, and 2 months. We did the treatment allocation using a web-based central randomisation system stratified by age (6 weeks-4 months, 5-17 months), and by baseline CD4% (vaccine recipient, their parent or carer, the funder, and investigators responsible for the assessment of endpoints were all masked to treatment allocation (only staff responsible for the preparation and administration of the vaccines were aware of the assignment and these individuals played no other role in the study). We provided ART, even if the participants were not receiving ART before the study, and daily co-trimoxazole for prevention of opportunistic infections. The primary outcome was the occurrence of serious adverse events until 14 months after dose 1 of the vaccine, assessed in the intention-to-treat population. This trial was registered

Intradermal HIV-1 DNA Immunization Using Needle-Free Zetajet Injection Followed by HIV-Modified Vaccinia Virus Ankara Vaccination Is Safe and Immunogenic in Mozambican Young Adults: A Phase I Randomized Controlled Trial.

Science.gov (United States)

Viegas, Edna Omar; Tembe, Nelson; Nilsson, Charlotta; Meggi, Bindiya; Maueia, Cremildo; Augusto, Orvalho; Stout, Richard; Scarlatti, Gabriella; Ferrari, Guido; Earl, Patricia L; Wahren, Britta; Andersson, Sören; Robb, Merlin L; Osman, Nafissa; Biberfeld, Gunnel; Jani, Ilesh; Sandström, Eric

2017-11-27

We assessed the safety and immunogenicity of HIV-DNA priming using Zetajet™, a needle-free device intradermally followed by intramuscular HIV-MVA boosts, in 24 healthy Mozambicans. Volunteers were randomized to receive three immunizations of 600 μg (n = 10; 2 × 0.1 ml) or 1,200 μg (n = 10; 2 × 0.2 ml) of HIV-DNA (3 mg/ml), followed by two boosts of 10 8 pfu HIV-MVA. Four subjects received placebo saline injections. Vaccines and injections were safe and well tolerated with no difference between the two priming groups. After three HIV-DNA immunizations, IFN-γ ELISpot responses to Gag were detected in 9/17 (53%) vaccinees, while none responded to Envelope (Env). After the first HIV-MVA, the overall response rate to Gag and/or Env increased to 14/15 (93%); 14/15 (93%) to Gag and 13/15 (87%) to Env. There were no significant differences between the immunization groups in frequency of response to Gag and Env or magnitude of Gag responses. Env responses were significantly higher in the higher dose group (median 420 vs. 157.5 SFC/million peripheral blood mononuclear cell, p = .014). HIV-specific antibodies to subtype C gp140 and subtype B gp160 were elicited in all vaccinees after the second HIV-MVA, without differences in titers between the groups. Neutralizing antibody responses were not detected. Two (13%) of 16 vaccinees, one in each of the priming groups, exhibited antibodies mediating antibody-dependent cellular cytotoxicity to CRF01_AE. In conclusion, HIV-DNA vaccine delivered intradermally in volumes of 0.1-0.2 ml using Zetajet was safe and well tolerated. Priming with the 1,200 μg dose of HIV-DNA generated higher magnitudes of ELISpot responses to Env.

Effects of the deletion of early region 4 (E4 open reading frame 1 (orf1, orf1-2, orf1-3 and orf1-4 on virus-host cell interaction, transgene expression, and immunogenicity of replicating adenovirus HIV vaccine vectors.

Directory of Open Access Journals (Sweden)

Michael A Thomas

Full Text Available The global health burden engendered by human immunodeficiency virus (HIV-induced acquired immunodeficiency syndrome (AIDS is a sobering reminder of the pressing need for a preventative vaccine. In non-human primate models replicating adenovirus (Ad-HIV/SIV recombinant vaccine vectors have been shown to stimulate potent immune responses culminating in protection against challenge exposures. Nonetheless, an increase in the transgene carrying capacity of these Ad vectors, currently limited to approximately 3000 base pairs, would greatly enhance their utility. Using a replicating, E3-deleted Ad type 5 host range mutant (Ad5 hr encoding full-length single-chain HIVBaLgp120 linked to the D1 and D2 domains of rhesus macaque CD4 (rhFLSC we systematically deleted the genes encoding early region 4 open reading frame 1 (E4orf1 through E4orf4. All the Ad-rhFLSC vectors produced similar levels of viral progeny. Cell cycle analysis of infected human and monkey cells revealed no differences in virus-host interaction. The parental and E4-deleted viruses expressed comparable levels of the transgene with kinetics similar to Ad late proteins. Similar levels of cellular immune responses and transgene-specific antibodies were elicited in vaccinated mice. However, differences in recognition of Ad proteins and induced antibody subtypes were observed, suggesting that the E4 gene products might modulate antibody responses by as yet unknown mechanisms. In short, we have improved the transgene carrying capacity by one thousand base pairs while preserving the replicability, levels of transgene expression, and immunogenicity critical to these vaccine vectors. This additional space allows for flexibility in vaccine design that could not be obtained with the current vector and as such should facilitate the goal of improving vaccine efficacy. To the best of our knowledge, this is the first report describing the effects of these E4 deletions on transgene expression and

Effects of the deletion of early region 4 (E4) open reading frame 1 (orf1), orf1-2, orf1-3 and orf1-4 on virus-host cell interaction, transgene expression, and immunogenicity of replicating adenovirus HIV vaccine vectors.

Science.gov (United States)

Thomas, Michael A; Song, Rui; Demberg, Thorsten; Vargas-Inchaustegui, Diego A; Venzon, David; Robert-Guroff, Marjorie

2013-01-01

The global health burden engendered by human immunodeficiency virus (HIV)-induced acquired immunodeficiency syndrome (AIDS) is a sobering reminder of the pressing need for a preventative vaccine. In non-human primate models replicating adenovirus (Ad)-HIV/SIV recombinant vaccine vectors have been shown to stimulate potent immune responses culminating in protection against challenge exposures. Nonetheless, an increase in the transgene carrying capacity of these Ad vectors, currently limited to approximately 3000 base pairs, would greatly enhance their utility. Using a replicating, E3-deleted Ad type 5 host range mutant (Ad5 hr) encoding full-length single-chain HIVBaLgp120 linked to the D1 and D2 domains of rhesus macaque CD4 (rhFLSC) we systematically deleted the genes encoding early region 4 open reading frame 1 (E4orf1) through E4orf4. All the Ad-rhFLSC vectors produced similar levels of viral progeny. Cell cycle analysis of infected human and monkey cells revealed no differences in virus-host interaction. The parental and E4-deleted viruses expressed comparable levels of the transgene with kinetics similar to Ad late proteins. Similar levels of cellular immune responses and transgene-specific antibodies were elicited in vaccinated mice. However, differences in recognition of Ad proteins and induced antibody subtypes were observed, suggesting that the E4 gene products might modulate antibody responses by as yet unknown mechanisms. In short, we have improved the transgene carrying capacity by one thousand base pairs while preserving the replicability, levels of transgene expression, and immunogenicity critical to these vaccine vectors. This additional space allows for flexibility in vaccine design that could not be obtained with the current vector and as such should facilitate the goal of improving vaccine efficacy. To the best of our knowledge, this is the first report describing the effects of these E4 deletions on transgene expression and immunogenicity in a

Projected economic evaluation of the national implementation of a hypothetical HIV vaccination program among adolescents in South Africa, 2012

Directory of Open Access Journals (Sweden)

Nishila Moodley

2016-04-01

Full Text Available Abstract Background Adolescents in South Africa are at high risk of acquiring HIV. The HIV vaccination of adolescents could reduce HIV incidence and mortality. The potential impact and cost-effectiveness of a national school-based HIV vaccination program among adolescents was determined. Method The national HIV disease and cost burden was compared with (intervention and without HIV vaccination (comparator given to school-going adolescents using a semi-Markov model. Life table analysis was conducted to determine the impact of the intervention on life expectancy. Model inputs included measures of disease and cost burden and hypothetical assumptions of vaccine characteristics. The base-case HIV vaccine modelled cost at US$ 12 per dose; vaccine efficacy of 50 %; duration of protection of 10 years achieved at a coverage rate of 60 % and required annual boosters. Incremental cost-effectiveness ratios (ICER were calculated using life years gained (LYG serving as the outcome measure. Sensitivity analyses were conducted on the vaccine characteristics to assess parameter uncertainty. Results The HIV vaccination model yielded an ICER of US$ 5 per LYG (95 % CI ZAR 2.77–11.61 compared with the comparator, which is considerably less than the national willingness-to-pay threshold of cost-effectiveness. This translated to an 11 % increase in per capita costs from US$ 80 to US$ 89. National implementation of this intervention could potentially result in an estimated cumulative gain of 23.6 million years of life (95 % CI 8.48–34.3 million years among adolescents age 10–19 years that were vaccinated. The 10 year absolute risk reduction projected by vaccine implementation was 0.42 % for HIV incidence and 0.41 % for HIV mortality, with an increase in life expectancy noted across all age groups. The ICER was sensitive to the vaccine efficacy, coverage and vaccine pricing in the sensitivity analysis. Conclusions A national HIV vaccination program would

Molecular Characterization of Heterologous HIV-1gp120 Gene Expression Disruption in Mycobacterium bovis BCG Host Strain: A Critical Issue for Engineering Mycobacterial Based-Vaccine Vectors

Science.gov (United States)

Joseph, Joan; Fernández-Lloris, Raquel; Pezzat, Elías; Saubi, Narcís; Cardona, Pere-Joan; Mothe, Beatriz; Gatell, Josep Maria

2010-01-01

Mycobacterium bovis Bacillus Calmette-Guérin (BCG) as a live vector of recombinant bacterial vaccine is a promising system to be used. In this study, we evaluate the disrupted expression of heterologous HIV-1gp120 gene in BCG Pasteur host strain using replicative vectors pMV261 and pJH222. pJH222 carries a lysine complementing gene in BCG lysine auxotrophs. The HIV-1 gp120 gene expression was regulated by BCG hsp60 promoter (in plasmid pMV261) and Mycobacteria spp. α-antigen promoter (in plasmid pJH222). Among 14 rBCG:HIV-1gp120 (pMV261) colonies screened, 12 showed a partial deletion and two showed a complete deletion. However, deletion was not observed in all 10 rBCG:HIV-1gp120 (pJH222) colonies screened. In this study, we demonstrated that E. coli/Mycobacterial expression vectors bearing a weak promoter and lysine complementing gene in a recombinant lysine auxotroph of BCG could prevent genetic rearrangements and disruption of HIV 1gp120 gene expression, a key issue for engineering Mycobacterial based vaccine vectors. PMID:20617151

Molecular Characterization of Heterologous HIV-1gp120 Gene Expression Disruption in Mycobacterium bovis BCG Host Strain: A Critical Issue for Engineering Mycobacterial Based-Vaccine Vectors

Directory of Open Access Journals (Sweden)

Joan Joseph

2010-01-01

Full Text Available Mycobacterium bovis Bacillus Calmette-Guérin (BCG as a live vector of recombinant bacterial vaccine is a promising system to be used. In this study, we evaluate the disrupted expression of heterologous HIV-1gp120 gene in BCG Pasteur host strain using replicative vectors pMV261 and pJH222. pJH222 carries a lysine complementing gene in BCG lysine auxotrophs. The HIV-1 gp120 gene expression was regulated by BCG hsp60 promoter (in plasmid pMV261 and Mycobacteria spp. α-antigen promoter (in plasmid pJH222. Among 14 rBCG:HIV-1gp120 (pMV261 colonies screened, 12 showed a partial deletion and two showed a complete deletion. However, deletion was not observed in all 10 rBCG:HIV-1gp120 (pJH222 colonies screened. In this study, we demonstrated that E. coli/Mycobacterial expression vectors bearing a weak promoter and lysine complementing gene in a recombinant lysine auxotroph of BCG could prevent genetic rearrangements and disruption of HIV 1gp120 gene expression, a key issue for engineering Mycobacterial based vaccine vectors.

Exploring barriers and facilitators to participation of male-to-female transgender persons in preventive HIV vaccine clinical trials.

Science.gov (United States)

Andrasik, Michele Peake; Yoon, Ro; Mooney, Jessica; Broder, Gail; Bolton, Marcus; Votto, Teress; Davis-Vogel, Annet

2014-06-01

Observed seroincidence and prevalence rates in male-to-female (MTF) transgender individuals highlight the need for effective targeted HIV prevention strategies for this community. In order to develop an effective vaccine that can be used by transgender women, researchers must understand and address existing structural issues that present barriers to this group's participation in HIV vaccine clinical trials. Overcoming barriers to participation is important for ensuring HIV vaccine acceptability and efficacy for the MTF transgender community. To explore barriers and facilitators to MTF transgender participation in preventive HIV vaccine clinical trials, the HIV Vaccine Trials Network conducted focus groups among transgender women in four urban areas (Atlanta, Boston, Philadelphia, and San Francisco). Barriers and facilitators to engagement of transgender women in preventive HIV vaccine clinical trials led to the following recommendations: (a) transgender cultural competency training, (b) creating trans-friendly environments, (c) true partnerships with local trans-friendly organizations and health care providers, (d) protocols that focus on transgender specific issues, and (e) data collection and tracking of transgender individuals. These results have implications for the conduct of HIV vaccine trials, as well as engagement of transgender women in research programs in general.

Antibodies to the HIV-1 Tat protein correlated with nonprogression to AIDS: a rationale for the use of Tat toxoid as an HIV-1 vaccine.

Science.gov (United States)

Zagury, J F; Sill, A; Blattner, W; Lachgar, A; Le Buanec, H; Richardson, M; Rappaport, J; Hendel, H; Bizzini, B; Gringeri, A; Carcagno, M; Criscuolo, M; Burny, A; Gallo, R C; Zagury, D

1998-01-01

To investigate which immune parameters, such as antibodies against HIV-1 specificities, or viral parameters, such as p24 antigenemia, are predictive of disease progression. We performed studies on serum collected from individuals exhibiting two extremes of disease evolution--67 fast progressors (FP) and 182 nonprogressors (NP)--at their enrollment. After a 1- to 2-year clinical follow-up of 104 nonprogressors after their enrollment, we could determine the best serologic predictors for disease progression. We investigated levels of antibodies to tetanus toxoid and to HIV antigens including Env, Gag, Nef, and Tat proteins, as well as p24 antigenemia, viremia, CD4 cell count, and interferon-alpha (IFN-alpha) titers in FPs and NPs, and we correlated these data with clinical and biologic signs of progression. p24 Antigenemia, a marker of viral replication, and anti-Tat antibodies were highly and inversely correlated in both groups (P < .001). Furthermore, anti-p24 antibodies and low serum IFN-alpha levels were correlated to the NP versus the FP cohort. Finally, among NPs, only antibodies to Tat and not to the other HIV specificities (Env, Nef, Gag) were significantly predictive of clinical stability during their follow-up. Antibodies toward HIV-1 Tat, which are inversely correlated to p24 antigenemia, appear as a critical marker for a lack of disease progression. This study strongly suggests that rising anti-Tat antibodies through active immunization may be beneficial in AIDS vaccine development to control viral replication.

HIV-1 Gag-specific exosome-targeted T cell-based vaccine stimulates effector CTL responses leading to therapeutic and long-term immunity against Gag/HLA-A2-expressing B16 melanoma in transgenic HLA-A2 mice

Directory of Open Access Journals (Sweden)

Rong Wang

2014-01-01

Full Text Available Human immunodeficiency virus type-1 (HIV-1-specific dendritic cell (DC vaccines have been applied to clinical trials that show only induction of some degree of immune responses, warranting the search of other more efficient vaccine strategies. Since HIV-1-specific CD8+ cytotoxic T lymphocytes (CTLs have been found to recognize some HIV-1 structural protein Gag conserved and cross-strain epitopes, Gag has become one of the most attractive target candidates for HIV-1 vaccine development. In this study, we generated HIV-1 Gag-specific Gag-Texo vaccine by using ConA-stimulated polyclonal CD8+ T-cells with uptake of Gag-expressing adenoviral vector AdVGag-transfected DC (DCGag-released exosomes (EXOs, and assessed its stimulation of Gag-specific CD8+ CTL responses and antitumor immunity. We demonstrate that Gag-Texo and DCGag vaccines comparably stimulate Gag-specific effector CD8+ CTL responses. Gag-Texo-stimulated CTL responses result in protective immunity against Gag-expressing BL6-10Gag melanoma in 8/8 wild-type C57BL/6 mice. In addition, we show that Gag-Texo vaccine also induces CTL responses leading to protective and long-term immunity against Gag/HLA-A2-expressing BL6-10Gag/A2 melanoma in 8/8 and 2/8 transgenic HLA-A2 mice, respectively. The average number of lung tumor colonies in mice with 30-days post-immunization is only 23, which is significantly less than that (>300 in control ConA-T-immunized HLA-A2 mice. Furthermore, Gag-Texo vaccine also induces some degree of therapeutic immunity. The average number (50 and size (0.23 mm in diameter of lung tumor colonies in Gag-Texo-immunized HLA-A2 mice bearing 6-day-established lung BL6-10Gag/A2 melanoma metastasis are significantly less than the average number (>300 and size (1.02 mm in diameter in control ConA-T-immunized HLA-A2 mice. Taken together, HIV-1 Gag-Texo vaccine capable of stimulating Gag-specific CTL responses and therapeutic immunity may be useful as a new immunotherapeutic

Antibody-Mediated Internalization of Infectious HIV-1 Virions Differs among Antibody Isotypes and Subclasses.

Science.gov (United States)

Tay, Matthew Zirui; Liu, Pinghuang; Williams, LaTonya D; McRaven, Michael D; Sawant, Sheetal; Gurley, Thaddeus C; Xu, Thomas T; Dennison, S Moses; Liao, Hua-Xin; Chenine, Agnès-Laurence; Alam, S Munir; Moody, M Anthony; Hope, Thomas J; Haynes, Barton F; Tomaras, Georgia D

2016-08-01

Emerging data support a role for antibody Fc-mediated antiviral activity in vaccine efficacy and in the control of HIV-1 replication by broadly neutralizing antibodies. Antibody-mediated virus internalization is an Fc-mediated function that may act at the portal of entry whereby effector cells may be triggered by pre-existing antibodies to prevent HIV-1 acquisition. Understanding the capacity of HIV-1 antibodies in mediating internalization of HIV-1 virions by primary monocytes is critical to understanding their full antiviral potency. Antibody isotypes/subclasses differ in functional profile, with consequences for their antiviral activity. For instance, in the RV144 vaccine trial that achieved partial efficacy, Env IgA correlated with increased risk of HIV-1 infection (i.e. decreased vaccine efficacy), whereas V1-V2 IgG3 correlated with decreased risk of HIV-1 infection (i.e. increased vaccine efficacy). Thus, understanding the different functional attributes of HIV-1 specific IgG1, IgG3 and IgA antibodies will help define the mechanisms of immune protection. Here, we utilized an in vitro flow cytometric method utilizing primary monocytes as phagocytes and infectious HIV-1 virions as targets to determine the capacity of Env IgA (IgA1, IgA2), IgG1 and IgG3 antibodies to mediate HIV-1 infectious virion internalization. Importantly, both broadly neutralizing antibodies (i.e. PG9, 2G12, CH31, VRC01 IgG) and non-broadly neutralizing antibodies (i.e. 7B2 mAb, mucosal HIV-1+ IgG) mediated internalization of HIV-1 virions. Furthermore, we found that Env IgG3 of multiple specificities (i.e. CD4bs, V1-V2 and gp41) mediated increased infectious virion internalization over Env IgG1 of the same specificity, while Env IgA mediated decreased infectious virion internalization compared to IgG1. These data demonstrate that antibody-mediated internalization of HIV-1 virions depends on antibody specificity and isotype. Evaluation of the phagocytic potency of vaccine

Durability of response to vaccination against viral hepatitis A in HIV-infected patients: a 5-year observation.

Science.gov (United States)

Jabłonowska, E; Kuydowicz, J

2014-09-01

The aim of this study was to estimate the prevalence of total antibodies to hepatitis A virus (anti-HAV-T) in the group of HIV-positive adults in Lodz region of Poland, and to evaluate the response and long-term immunity after vaccination against hepatitis A virus. In the group of 234 HIV-infected patients, 72 persons (30.8%) were anti-HAV-T positive (>20 IU/L). In multivariate analysis, two independent factors associated with the presence of anti-HAV-T were identified: the age of patients (OR = 1.07) and the presence of antibodies to hepatitis C virus (OR = 2.87). Vaccination was completed in 83 patients. Good response (anti-HAV-T >20 IU/L one month after the booster dose) was obtained in 79.5% of patients. In patients with CD4 >200 cells/µL in multivariate analysis only presence of antibodies to hepatitis C virus was a prognostic factor for the response to vaccination (OR = 0.13). Among responders available for the follow-up, 82% (50 out of 61) had detectable anti-HAV-T at 1 year and 75.5% (37 out of 49) at 5 years. Our results demonstrate that most of the studied HIV-positive patients were susceptible to hepatitis A virus infection. Most HIV-infected adults with high CD4 counts had a durable response even up to 5 years after vaccination. Patients with a HIV/hepatitis C virus coinfection displayed a worse response to vaccination. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

HIV vaccine trial willingness among injection and non-injection drug users in two urban centres, Barcelona and San Francisco.

Science.gov (United States)

Etcheverry, M Florencia; Lum, Paula J; Evans, Jennifer L; Sanchez, Emilia; de Lazzari, Elisa; Mendez-Arancibia, Eva; Sierra, Ernesto; Gatell, José M; Page, Kimberly; Joseph, Joan

2011-02-24

Being able to recruit high-risk volunteers who are also willing to consider future participation in vaccine trials are critical features of vaccine preparedness studies. We described data from two cohorts of injection- and non-injection drug users in Barcelona, Spain [Red Cross centre] and in San Francisco, USA, [UFO-VAX study] at high risk of HIV/HCV infection to assess behaviour risk exposure and willingness to participate in future preventive HIV vaccine trials. We successfully identified drug-using populations that would be eligible for future HIV vaccine efficacy trials, based on reported levels of risk during screening and high levels of willingness to participate. In both groups, Red Cross and UFO-VAX respectively, HCV infection was highly prevalent at baseline (41% and 34%), HIV baseline seroprevalence was 4.2% and 1.5%, and high levels of willingness were seen (83% and 78%). Copyright © 2011 Elsevier Ltd. All rights reserved.

HIV-1 Subtype C Mosaic Gag Expressed by BCG and MVA Elicits Persistent Effector T Cell Responses in a Prime-Boost Regimen in Mice.

Directory of Open Access Journals (Sweden)

Tsungai Ivai Jongwe

Full Text Available Over 90% of HIV/AIDS positive individuals in sub-Saharan Africa are infected with highly heterogeneous HIV-1 subtype C (HIV-1C viruses. One of the best ways to reduce the burden of this disease is the development of an affordable and effective prophylactic vaccine. Mosaic immunogens are computationally designed to overcome the hurdle of HIV diversity by maximizing the expression of potential T cell epitopes. Mycobacterium bovis BCG ΔpanCD auxotroph and modified vaccinia Ankara (MVA vaccines expressing HIV-1C mosaic Gag (GagM were tested in a prime-boost regimen to demonstrate immunogenicity in a mouse study. The BCG-GagM vaccine was stable and persisted 11.5 weeks post vaccination in BALB/c mice. Priming with BCG-GagM and boosting with MVA-GagM elicited higher Gag-specific IFN-γ ELISPOT responses than the BCG-GagM only and MVA-GagM only homologous vaccination regimens. The heterologous vaccination also generated a more balanced and persistent CD4+ and CD8+ T cell Gag-specific IFN-γ ELISPOT response with a predominant effector memory phenotype. A Th1 bias was induced by the vaccines as determined by the predominant secretion of IFN-γ, TNF-α, and IL-2. This study shows that a low dose of MVA (104 pfu can effectively boost a BCG prime expressing the same mosaic immunogen, generating strong, cellular immune responses against Gag in mice. Our data warrants further evaluation in non-human primates. A low dose vaccine would be an advantage in the resource limited countries of sub-Saharan Africa and India (where the predominating virus is HIV-1 subtype C.

Recombination of HIV type 1C (C'/C") in Ethiopia: possible link of EthHIV-1C' to subtype C sequences from the high-prevalence epidemics in India and Southern Africa

NARCIS (Netherlands)

Pollakis, Georgios; Abebe, Almaz; Kliphuis, Aletta; Rinke de Wit, Tobias F.; Fisseha, Bitew; Tegbaru, Belete; Tesfaye, Girma; Negassa, Hailu; Mengistu, Yohannes; Fontanet, Arnaud L.; Cornelissen, Marion; Goudsmit, Jaap

2003-01-01

The magnitude and complexity of the HIV-1 genetic diversity are major challenges for vaccine development. Investigation of the genotypes circulating in areas of high incidence, as well as their interactions, will be a milestone in the development of an efficacious vaccine. Because HIV-1 subtype C

Non-immunogenicity of overlapping gag peptides pulsed on autologous cells after vaccination of HIV infected individuals.

Directory of Open Access Journals (Sweden)

Henrik N Kløverpris

Full Text Available HIV Gag-specific CD4+ and CD8+ T-cell responses are important for HIV immune control. Pulsing overlapping Gag peptides on autologous lymphocytes (OPAL has proven immunogenic and effective in reducing viral loads in multiple pigtail macaque studies, warranting clinical evaluation.We performed a phase I, single centre, placebo-controlled, double-blinded and dose-escalating study to evaluate the safety and preliminary immunogenicity of a novel therapeutic vaccine approach 'OPAL-HIV-Gag(c'. This vaccine is comprised of 120 15mer peptides, overlapping by 11 amino acids, spanning the HIV Gag C clade sequence proteome, pulsed on white blood cells enriched from whole blood using a closed system, followed by intravenous reinfusion. Patients with undetectable HIV viral loads (<50 copies/ml plasma on HAART received four administrations at week 0, 4, 8 and 12, and were followed up for 12 weeks post-treatment. Twenty-three people were enrolled in four groups: 12 mg (n = 6, 24 mg (n = 7, 48 mg (n = 2 or matching placebo (n = 8 with 18 immunologically evaluable. T-cell immunogenicity was assessed by IFNγ ELIspot and intracellular cytokine staining (ICS.The OPAL-HIV-Gag(c peptides were antigenic in vitro in 17/17 subjects. After vaccination with OPAL-HIV-Gag(c, 1/6 subjects at 12 mg and 1/6 subjects at 24 mg dose groups had a 2- and 3-fold increase in ELIspot magnitudes from baseline, respectively, of Gag-specific CD8+ T-cells at week 14, compared to 0/6 subjects in the placebo group. No Gag-specific CD4+ T-cell responses or overall change in Rev, Nef, Tat and CMV specific responses were detected. Marked, transient and self-limiting lymphopenia was observed immediately post-vaccination (4 hours in OPAL-HIV-Gag(c but not in placebo recipients, with median fall from 1.72 to 0.67 million lymphocytes/mL for active groups (P<0.001, compared to post-placebo from 1.70 to 1.56 lymphocytes/ml (P = 0.16.Despite strong immunogenicity observed in

Capacity building among african american faith leaders to promote HIV prevention and vaccine research.

Science.gov (United States)

Alio, Amina P; Lewis, Cindi A; Bunce, Catherine A; Wakefield, Steven; Thomas, Weldon G; Sanders, Edwin; Keefer, Michael C

2014-01-01

In light of the increasing rates of HIV infection in African Americans, it is essential that black faith leaders become more proactive in the fight against the epidemic. The study aim was to engage faith leaders in a sustainable partnership to increase community participation in preventive HIV vaccine clinical research while improving their access to and utilization of HIV/AIDS prevention services. Leadership Development Seminars were adapted for faith leaders in Rochester, NY, with topics ranging from the importance of preventive HIV vaccine research to social issues surrounding HIV/AIDs within a theological framework. Seminars were taught by field-specific experts from the black community and included the development of action plans to institute HIV preventive ministries. To assess the outcome of the Seminars, baseline and post-training surveys were administered and analyzed through paired sample t Tests and informal interviews. 19 faith leaders completed the intervention. In general, the majority of clergy felt that their understanding of HIV vaccine research and its goals had increased postintervention. A critical outcome was the subsequent formation of the Rochester Faith Collaborative by participating clergy seeking to sustain the collaborative and address the implementation of community action plans. Providing scientific HIV/AIDS knowledge within the context of clergy members' belief structure was an effective method for engaging black Church leaders in Rochester, NY. Collaborative efforts with various local institutions and community-based organizations were essential in building trust with the faith leaders, thereby building bridges for better understanding of HIV/AIDS prevention efforts, including HIV vaccine research.

Factors associated with self-reported HBV vaccination among HIV-negative MSM participating in an online sexual health survey: a cross-sectional study.

Directory of Open Access Journals (Sweden)

Jonathan E Matthews

Full Text Available A substantial proportion of men who have sex with men (MSM in the United States remain unvaccinated against hepatitis B. We sought to understand which factors are associated with vaccination among HIV-negative MSM.Data were from a 2010 web-based survey of adult MSM. We calculated the prevalence of self-reported hepatitis B vaccination among 1,052 HIV-negative or HIV-untested men who knew their hepatitis B vaccination status, and used multivariate logistic regression to determine associated factors. 679 (64.5% MSM reported being vaccinated. Younger men were more likely to report being vaccinated than older men, and there was a significant interaction between age and history of hepatitis B testing. Men with at least some college education were at least 2.1 times as likely to be vaccinated as men with a high school education or less (95% CI = 1.4-3.1. Provider recommendation for vaccination (aOR = 4.2, 95% CI = 2.4-7.4 was also significantly associated with receipt of vaccination.Providers should assess sexual histories of male patients and offer those patients with male sex partners testing for hepatitis infection and vaccinate susceptible patients. There may be particular opportunities for screening and vaccination among older and more socioeconomically disadvantaged MSM.

Frequent intra-subtype recombination among HIV-1 circulating in Tanzania.

Directory of Open Access Journals (Sweden)

Ireen E Kiwelu

Full Text Available The study estimated the prevalence of HIV-1 intra-subtype recombinant variants among female bar and hotel workers in Tanzania. While intra-subtype recombination occurs in HIV-1, it is generally underestimated. HIV-1 env gp120 V1-C5 quasispecies from 45 subjects were generated by single-genome amplification and sequencing (median (IQR of 38 (28-50 sequences per subject. Recombination analysis was performed using seven methods implemented within the recombination detection program version 3, RDP3. HIV-1 sequences were considered recombinant if recombination signals were detected by at least three methods with p-values of ≤0.05 after Bonferroni correction for multiple comparisons. HIV-1 in 38 (84% subjects showed evidence for intra-subtype recombination including 22 with HIV-1 subtype A1, 13 with HIV-1 subtype C, and 3 with HIV-1 subtype D. The distribution of intra-patient recombination breakpoints suggested ongoing recombination and showed selective enrichment of recombinant variants in 23 (60% subjects. The number of subjects with evidence of intra-subtype recombination increased from 29 (69% to 36 (82% over one year of follow-up, although the increase did not reach statistical significance. Adjustment for intra-subtype recombination is important for the analysis of multiplicity of HIV infection. This is the first report of high prevalence of intra-subtype recombination in the HIV/AIDS epidemic in Tanzania, a region where multiple HIV-1 subtypes co-circulate. HIV-1 intra-subtype recombination increases viral diversity and presents additional challenges for HIV-1 vaccine design.

Stable 293 T and CHO cell lines expressing cleaved, stable HIV-1 envelope glycoprotein trimers for structural and vaccine studies

NARCIS (Netherlands)

Chung, Nancy P. Y.; Matthews, Katie; Kim, Helen J.; Ketas, Thomas J.; Golabek, Michael; de Los Reyes, Kevin; Korzun, Jacob; Yasmeen, Anila; Sanders, Rogier W.; Klasse, Per Johan; Wilson, Ian A.; Ward, Andrew B.; Marozsan, Andre J.; Moore, John P.; Cupo, Albert

2014-01-01

Recombinant soluble, cleaved HIV-1 envelope glycoprotein SOSIP.664 gp140 trimers based on the subtype A BG505 sequence are being studied structurally and tested as immunogens in animals. For these trimers to become a vaccine candidate for human trials, they would need to be made in appropriate

Co-evolution of a broadly neutralizing HIV-1 antibody and founder virus

Science.gov (United States)

Liao, Hua-Xin; Lynch, Rebecca; Zhou, Tongqing; Gao, Feng; Alam, S. Munir; Boyd, Scott D.; Fire, Andrew Z.; Roskin, Krishna M.; Schramm, Chaim A.; Zhang, Zhenhai; Zhu, Jiang; Shapiro, Lawrence; Mullikin, James C.; Gnanakaran, S.; Hraber, Peter; Wiehe, Kevin; Kelsoe, Garnett; Yang, Guang; Xia, Shi-Mao; Montefiori, David C.; Parks, Robert; Lloyd, Krissey E.; Scearce, Richard M.; Soderberg, Kelly A.; Cohen, Myron; Kaminga, Gift; Louder, Mark K.; Tran, Lillan M.; Chen, Yue; Cai, Fangping; Chen, Sheri; Moquin, Stephanie; Du, Xiulian; Joyce, Gordon M.; Srivatsan, Sanjay; Zhang, Baoshan; Zheng, Anqi; Shaw, George M.; Hahn, Beatrice H.; Kepler, Thomas B.; Korber, Bette T.M.; Kwong, Peter D.; Mascola, John R.; Haynes, Barton F.

2013-01-01

Current HIV-1 vaccines elicit strain-specific neutralizing antibodies. However, cross-reactive neutralizing antibodies arise in ~20% of HIV-1-infected individuals, and details of their generation could provide a roadmap for effective vaccination. Here we report the isolation, evolution and structure of a broadly neutralizing antibody from an African donor followed from time of infection. The mature antibody, CH103, neutralized ~55% of HIV-1 isolates, and its co-crystal structure with gp120 revealed a novel loop-based mechanism of CD4-binding site recognition. Virus and antibody gene sequencing revealed concomitant virus evolution and antibody maturation. Notably, the CH103-lineage unmutated common ancestor avidly bound the transmitted/founder HIV-1 envelope glycoprotein, and evolution of antibody neutralization breadth was preceded by extensive viral diversification in and near the CH103 epitope. These data elucidate the viral and antibody evolution leading to induction of a lineage of HIV-1 broadly neutralizing antibodies and provide insights into strategies to elicit similar antibodies via vaccination. PMID:23552890

Impact of a new vaccine clinic on hepatitis B vaccine completion and immunological response rates in an HIV-positive cohort.

Science.gov (United States)

Rock, Clare; de Barra, Eoghan; Sadlier, Corinna; Kelly, Sinead; Dowling, Catherine; McNally, Cora; Bergin, Colm

2013-06-01

Hepatitis B virus vaccination (HBVV) in the HIV-infected population has poor reported completion rates and immunological response rates. At our HIV clinic, we established a vaccine clinic to improve HBVV outcomes using interventions such as SMS text reminders and double-dose (DD) HBVV for standard-dose non-responders (SD NRs). A five-year (2003-2008) retrospective review of the completion rates and immunological response rates for HBVV after the establishment of the dedicated vaccine clinic was conducted. Statistical significance was assumed at presponse rate to DD HBVV among SD NRs. On-treatment analysis showed an 88% (155/176) overall immunological response to SD HBVV and DD HBVV, if required. High HBVV completion and response rates in this HIV cohort were enabled through the use of multiple interventions, including the use of SMS text message reminders and routine referral for DD vaccination. Copyright © 2012 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

Broadening of the T-cell repertoire to HIV-1 Gag p24 by vaccination of HLA-A2/DR transgenic mice with overlapping peptides in the CAF05 adjuvant

DEFF Research Database (Denmark)

Korsholm, Karen S; Karlsson, Ingrid; Tang, Sheila T

2013-01-01

Induction of broad T-cell immune responses is regarded as critical for vaccines against the human immunodeficiency virus type 1 (HIV-1) which exhibit high diversity and, therefore, focus has been on inducing cytotoxic CD8 T-cell responses against the more conserved parts of the virus, such as the....../DR-transgenic mouse model. Thus, combining overlapping Gag p24 peptides with CAF05 appears to be a promising and simple strategy for inducing broader T-cell responses to multiple conserved epitopes which will be relevant for both prophylactic and therapeutic HIV-1 vaccines....

A brief history of the global effort to develop a preventive HIV vaccine.

Science.gov (United States)

Esparza, José

2013-08-02

Soon after HIV was discovered as the cause of AIDS in 1983-1984, there was an expectation that a preventive vaccine would be rapidly developed. In trying to achieve that goal, three successive scientific paradigms have been explored: induction of neutralizing antibodies, induction of cell mediated immunity, and exploration of combination approaches and novel concepts. Although major progress has been made in understanding the scientific basis for HIV vaccine development, efficacy trials have been critical in moving the field forward. In 2009, the field was reinvigorated with the modest results obtained from the RV144 trial conducted in Thailand. Here, we review those vaccine development efforts, with an emphasis on events that occurred during the earlier years. The goal is to provide younger generations of scientists with information and inspiration to continue the search for an HIV vaccine. Copyright © 2013 The Author. Published by Elsevier Ltd.. All rights reserved.

A Phase III, randomized study to evaluate the immunogenicity and safety of an MF59®-adjuvanted A/H1N1 pandemic influenza vaccine in HIV-positive adults

Directory of Open Access Journals (Sweden)

Ricardo Sobhie Diaz

2014-01-01

Conclusion: Antibody responses in HIV-positive subjects were acceptable but lower than those in healthy control subjects, whether subjects were immunized with one or two doses of adjuvanted or unadjuvanted vaccine. Vaccination did not affect rates of HIV replication, CD4+ T cells counts, or levels of CD38 expression among patients under successful antiretroviral treatment.

A phase I randomized clinical trial of candidate human immunodeficiency virus type 1 vaccine MVA.HIVA administered to Gambian infants.

Directory of Open Access Journals (Sweden)

Muhammed O Afolabi

Full Text Available A vaccine to decrease transmission of human immunodeficiency virus type 1 (HIV-1 during breast-feeding would complement efforts to eliminate infant HIV-1 infection by antiretroviral therapy. Relative to adults, infants have distinct immune development, potentially high-risk of transmission when exposed to HIV-1 and rapid progression to AIDS when infected. To date, there have been only three published HIV-1 vaccine trials in infants.We conducted a randomized phase I clinical trial PedVacc 001 assessing the feasibility, safety and immunogenicity of a single dose of candidate vaccine MVA.HIVA administered intramuscularly to 20-week-old infants born to HIV-1-negative mothers in The Gambia.Infants were followed to 9 months of age with assessment of safety, immunogenicity and interference with Expanded Program on Immunization (EPI vaccines. The trial is the first stage of developing more complex prime-boost vaccination strategies against breast milk transmission of HIV-1.From March to October 2010, 48 infants (24 vaccine and 24 no-treatment were enrolled with 100% retention. The MVA.HIVA vaccine was safe with no difference in adverse events between vaccinees and untreated infants. Two vaccine recipients (9% and no controls had positive ex vivo interferon-γ ELISPOT assay responses. Antibody levels elicited to the EPI vaccines, which included diphtheria, tetanus, whole-cell pertussis, hepatitis B virus, Haemophilus influenzae type b and oral poliovirus, reached protective levels for the vast majority and were similar between the two arms.A single low-dose of MVA.HIVA administered to 20-week-old infants in The Gambia was found to be safe and without interference with the induction of protective antibody levels by EPI vaccines, but did not alone induce sufficient HIV-1-specific responses. These data support the use of MVA carrying other transgenes as a boosting vector within more complex prime-boost vaccine strategies against transmission of HIV-1 and

Recent progress in immune-based interventions to prevent HIV-1 transmission to children.

Science.gov (United States)

Voronin, Yegor; Jani, Ilesh; Graham, Barney S; Cunningham, Coleen K; Mofenson, Lynne M; Musoke, Philippa M; Permar, Sallie R; Scarlatti, Gabriella

2017-12-01

Globally, 150,000 new paediatric human immunodeficiency virus type 1 (HIV-1) infections occurred in 2015. There remain complex challenges to the global elimination of paediatric HIV-1 infection. Thus, for the global community to achieve elimination of new paediatric HIV-1 infections, innovative approaches need to be explored. Immune-based approaches to prevention of mother-to-child transmission (MTCT) may help fill some of the remaining gaps and provide new opportunities to achieve an AIDS-free generation. Immune-based interventions to prevent MTCT of HIV-1 may include paediatric HIV vaccines and passive immunization approaches. Recent discoveries providing evidence of robust immune responses to HIV in infants open new and exciting prospects for paediatric HIV vaccines. Moreover, successful vaccination of infants has a different set of requirements than vaccination of adults and may be easier to achieve. Proof-of-concept has been established over the last two decades that passively administered HIV-1 Env-specific monoclonal antibody (mAbs) can prevent chimeric simian human immunodeficiency virus (SHIV) transmission to newborn nonhuman primates. There has been tremendous progress in isolating and characterizing broadly neutralizing antibodies to HIV, and clinical testing of these antibodies for treatment and prevention in both infants and adults is a major effort in the field. Immune-based interventions need to be actively explored as they can provide critically important tools to address persistent challenges in MTCT prevention. It is a pivotal time for the field with active discussions on the best strategy to further reduce HIV infection of infants and accomplish the World Health Organization Fast-Track 2030 goals to eliminate new paediatric HIV infections. © 2017 The Authors. Journal of the International AIDS Society published by John Wiley & sons Ltd on behalf of the International AIDS Society.

1 original article diverse genetic subtypes of hiv-1 among female sex

African Journals Online (AJOL)

boaz

Keywords: Diverse, HIV, subtypes, Female Sex workers and Vaccine ... significant probability that infection with this subtype occurred with a short incubation period (p< 0.05). Conclusion: This study .... regression was used to adjust for potential cofounders. .... TABLE 2: DISTRIBUTION OF HIV-1 SUBTYPES AMONG FSWS.

A Randomized, Controlled Safety, and Immunogenicity Trial of the M72/AS01 Candidate Tuberculosis Vaccine in HIV-Positive Indian Adults.

Science.gov (United States)

Kumarasamy, Nagalingeswaran; Poongulali, Selvamuthu; Bollaerts, Anne; Moris, Philippe; Beulah, Faith Esther; Ayuk, Leo Njock; Demoitié, Marie-Ange; Jongert, Erik; Ofori-Anyinam, Opokua

2016-01-01

Human immunodeficiency virus (HIV)-associated tuberculosis is a major public health threat. We evaluated the safety and immunogenicity of the candidate tuberculosis vaccine M72/AS01 in HIV-positive and HIV-negative Indian adults.Randomized, controlled observer-blind trial (NCT01262976).We assigned 240 adults (1:1:1) to antiretroviral therapy (ART)-stable, ART-naive, or HIV-negative cohorts. Cohorts were randomized 1:1 to receive M72/AS01 or placebo following a 0, 1-month schedule and followed for 12 months (time-point M13). HIV-specific and laboratory safety parameters, adverse events (AEs), and M72-specific T-cell-mediated and humoral responses were evaluated.Subjects were predominantly QuantiFERON-negative (60%) and Bacille Calmette-Guérin-vaccinated (73%). Seventy ART-stable, 73 ART-naive, and 60 HIV-negative subjects completed year 1. No vaccine-related serious AEs or ART-regimen adjustments, or clinically relevant effects on laboratory parameters, HIV-1 viral loads or CD4 counts were recorded. Two ART-naive vaccinees died of vaccine-unrelated diseases. M72/AS01 induced polyfunctional M72-specific CD4 T-cell responses (median [interquartile range] at 7 days postdose 2: ART-stable, 0.9% [0.7-1.5]; ART-naive, 0.5% [0.2-1.0]; and HIV-negative, 0.6% [0.4-1.1]), persisting at M13 (0.4% [0.2-0.5], 0.09% [0.04-0.2], and 0.1% [0.09-0.2], respectively). Median responses were higher in the ART-stable cohort versus ART-naive cohort from day 30 onwards (P ≤ 0.015). Among HIV-positive subjects (irrespective of ART-status), median responses were higher in QuantiFERON-positive versus QuantiFERON-negative subjects up to day 30 (P ≤ 0.040), but comparable thereafter. Cytokine-expression profiles were comparable between cohorts after dose 2. At M13, M72-specific IgG responses were higher in ART-stable and HIV-negative vaccinees versus ART-naive vaccinees (P ≤ 0.001).M72/AS01 was well-tolerated and immunogenic in this population of ART-stable and ART-naive HIV

An Outdated Notion of Antibody Specificity is One of the Major Detrimental Assumptions of the Structure-Based Reverse Vaccinology Paradigm, Which Prevented It from Helping to Develop an Effective HIV-1 Vaccine.

Science.gov (United States)

Van Regenmortel, Marc H V

2014-01-01

The importance of paradigms for guiding scientific research is explained with reference to the seminal work of Karl Popper and Thomas Kuhn. A prevalent paradigm, followed for more than a decade in HIV-1 vaccine research, which gave rise to the strategy known as structure-based reverse vaccinology is described in detail. Several reasons why this paradigm did not allow the development of an effective HIV-1 vaccine are analyzed. A major reason is the belief shared by many vaccinologists that antibodies possess a narrow specificity for a single epitope and are not polyspecific for a diverse group of potential epitopes. When this belief is abandoned, it becomes obvious that the one particular epitope structure observed during the crystallographic analysis of a neutralizing antibody-antigen complex does not necessarily reveal, which immunogenic structure should be used to elicit the same type of neutralizing antibody. In the physical sciences, scientific explanations are usually presented as logical deductions derived from a relevant law of nature together with certain initial conditions. In immunology, causal explanations in terms of a single cause acting according to a law of nature are not possible because numerous factors always play a role in bringing about an effect. The implications of this state of affairs for the rational design of HIV vaccines are outlined. An alternative approach to obtain useful scientific understanding consists in intervening empirically in the immune system and it is suggested that manipulating the system experimentally is needed to learn to control it and achieve protective immunity by vaccination.

An outdated notion of antibody specificity is one of the major detrimental assumptions of the structure-based reverse vaccinology paradigm which prevented it from helping to develop an effective HIV-1 vaccine

Directory of Open Access Journals (Sweden)

Marc H V Van Regenmortel

2014-11-01

Full Text Available The importance of paradigms for guiding scientific research is explained with reference to the seminal work of Karl Popper and Thomas Kuhn. A prevalent paradigm, followed for more than a decade in HIV-1 vaccine research, which gave rise to the strategy known as structure-based reverse vaccinology is described in detail. Several reasons why this paradigm did not allow the development of an effective HIV-1 vaccine are analyzed. A major reason is the belief shared by many vaccinologists that antibodies possess a narrow specificity for a single epitope and are not polyspecific for a diverse group of potential epitopes. When this belief is abandoned, it becomes obvious that the one particular epitope structure observed during the crystallographic analysis of a neutralizing antibody-antigen complex does not necessarily reveal which immunogenic structure should be used to elicit the same type of neutralizing antibody.In the physical sciences, scientific explanations are usually presented as logical deductions derived from a relevant law of nature together with certain initial conditions. In immunology, causal explanations in terms of a single cause acting according to a law of nature are not possible because numerous factors always play a role in bringing about an effect. The implications of this state of affairs for the rational design of HIV vaccines are outlined. An alternative approach to obtain useful scientific understanding consists in intervening empirically in the immune system and it is suggested that manipulating the system experimentally is needed to learn to control it and achieve protective immunity by vaccination.

Risk factors for pneumococcal nasopharyngeal colonization before and after pneumococcal conjugate vaccination in persons with HIV

DEFF Research Database (Denmark)

Öbrink-Hansen, Kristina; Søgaard, Ole S; Harboe, Zitta B

HIV-infected individuals have excess rates of invasive pneumococcal disease. We investigated risk factors for nasopharyngeal pneumococcal colonization at baseline and after 9 months in 96 HIV patients immunized twice with 7- valent pneumococcal conjugate vaccine ±1mg CPG 7909. In total, 22 patients...

A combinatorial approach to the design of vaccines.

Science.gov (United States)

Martínez, Luis; Milanič, Martin; Legarreta, Leire; Medvedev, Paul; Malaina, Iker; de la Fuente, Ildefonso M

2015-05-01

We present two new problems of combinatorial optimization and discuss their applications to the computational design of vaccines. In the shortest λ-superstring problem, given a family S1,...,S(k) of strings over a finite alphabet, a set Τ of "target" strings over that alphabet, and an integer λ, the task is to find a string of minimum length containing, for each i, at least λ target strings as substrings of S(i). In the shortest λ-cover superstring problem, given a collection X1,...,X(n) of finite sets of strings over a finite alphabet and an integer λ, the task is to find a string of minimum length containing, for each i, at least λ elements of X(i) as substrings. The two problems are polynomially equivalent, and the shortest λ-cover superstring problem is a common generalization of two well known combinatorial optimization problems, the shortest common superstring problem and the set cover problem. We present two approaches to obtain exact or approximate solutions to the shortest λ-superstring and λ-cover superstring problems: one based on integer programming, and a hill-climbing algorithm. An application is given to the computational design of vaccines and the algorithms are applied to experimental data taken from patients infected by H5N1 and HIV-1.

Development of an HIV-1 Subtype Panel in China: Isolation and Characterization of 30 HIV-1 Primary Strains Circulating in China.

Directory of Open Access Journals (Sweden)

Jingwan Han

Full Text Available The complex epidemic and significant diversity of HIV-1 strains in China pose serious challenges for surveillance and diagnostic assays, vaccine development and clinical management. There is a lack of HIV-1 isolates in current canonical HIV-1 subtype panels that can represent HIV-1 diversity in China; an HIV-1 subtype panel for China is urgently needed.Blood samples were collected from HIV-1 infected patients participating in the drug-resistance surveillance program in China. The samples were isolated, cultured and stored as neat culture supernatant. The HIV-1 isolates were fully characterized. The panel was used to compare 2 viral load assays and 2 p24 assays as the examples of how this panel could be used.An HIV-1 subtype panel for China composed of 30 HIV-1 primary strains of four subtypes (B [including Thai-B], CRF01_AE, CRF07_BC and G was established. The samples were isolated and cultured to a high-titer (10(6-10(9 copies/ml/high-volume (40 ml. The HIV-1 isolates were fully characterized by the final viral load, p24 concentration, gag-pol and envC2V3 sequencing, co-receptor prediction, determination of the four amino acids at the tip of the env V3-loop, glycosylation sites in the V3 loop and the drug-resistance mutations. The comparison of two p24 assays and two viral load assays on the isolates illustrated how this panel may be used for the evaluation of diagnostic assay performance. The Pearson value between p24 assays were 0.938. The viral load results showed excellent concordance and agreement for samples of Thai-B, but lower correlations for samples of CRF01_AE.The current panel of 30 HIV-1 isolates served as a basis for the development of a comprehensive panel of fully characterized viral isolates, which could reflect the current dynamic and complex HIV-1 epidemic in China. This panel will be available to support HIV-1 research, assay evaluation, vaccine and drug development.

Characterization of near full-length genomes of HIV type 1 strains in Denmark: Basis for a universal therapeutic vaccine

DEFF Research Database (Denmark)

Andresen, Betina S.; Vinner, Lasse; Tang, Sheila Tuyet

2007-01-01

We report here the near full-length sequence characterization of 17 Danish clinical HIV-1 strains isolated from HLA-A02 patients not in need of ART, with relatively low viral loads and normal CD4 cell counts. Sequencing was performed directly on DNA extracted from short-term cocultures of PBMCs...... of a universal immunotherapeutic vaccine construct based on these epitopes....

Soil transmitted helminth infections are not associated with compromised antibody responses to previously administered measles and tetanus vaccines among HIV-1 infected, ART naïve Kenyan adults

Directory of Open Access Journals (Sweden)

Helen L. Storey

2017-02-01

Full Text Available In many regions of sub-Saharan Africa, both HIV and helminth infections are prevalent. HIV-1 (human immunodeficiency virus type 1 and helminth infections can both compromise immune responses in humans. To determine whether the presence of helminth infection or the treatment of helminth infection alters unstimulated vaccine responses among HIV-1 infected individuals, we conducted two nested serologic studies. Blood samples were collected for HIV disease monitoring and vaccine-specific serologic assays, while stool was evaluated by direct microscopy methods. We compared antibody responses to measles and tetanus vaccines in helminth-infected (Ascaris, Trichuris, hookworm and/or Schistosoma mansoni and uninfected adults 18 years and older (n = 100. We also compared measles and tetanus antibody responses in Ascaris only-infected adults receiving 400 mg albendazole daily for 3 days (n = 16 vs. placebo (n = 19 in a separate study. In both cohorts, over 70% of participants had measles and tetanus responses above the protective threshold. Prevalence of measles responses were similar between helminth-infected and uninfected individuals (82%, 95% CI: 71–93% vs 72%, 95% CI: 59–85%, as well as log10 tetanus antibody levels (−0.133 IU/mL vs −0.190 IU/mL, p > 0.05, and did not differ by helminth species. In the Ascaris-infected cohort, changes in measles responses and tetanus responses did not differ between those who received anthelminthic vs. placebo (p > 0.05 for both. In these studies, neither helminth infection, nor deworming, appeared to affect previously administered vaccine responsiveness in HIV-1 infected, ART naïve, adults in Kenya.

Immunogenicity and safety of yellow fever vaccine among 115 HIV-infected patients after a preventive immunisation campaign in Mali.

Science.gov (United States)

Sidibe, Mariam; Yactayo, Sergio; Kalle, Abdoulaye; Sall, Amadou A; Sow, Samba; Ndoutabe, Modjirom; Perea, William; Avokey, Fenella; Lewis, Rosamund F; Veit, Olivia

2012-07-01

The immune response to yellow fever (YF) vaccine and its safety among HIV-infected individuals living in YF endemic areas is not well understood. Following a national YF preventive immunisation campaign in Mali in April 2008, we assessed the immunogenicity and safety of 17D yellow fever vaccine (17DV) among HIV-infected patients in two HIV treatment centres in Bamako, Mali, by testing for neutralising antibodies and identifying serious adverse events following immunisation (AEFI). A YF neutralisation titre (NT) of 1:≥20 was considered to be adequate and protective. A serious AEFI included hospitalisation, any life-threatening condition, or death, occurring within 30 days following 17DV administration. Of 115 HIV-infected patients who reported having received 17DV, 110 (96%) were on combination antiretroviral therapy and 83 patients were tested for neutralising antibodies. Around the time of vaccination, median CD4 cell count was 389 cells/mm(3) (IQR 227-511cells/mm(3)); HIV-RNA was undetectable in 24 of 46 patients tested. Seventy-six (92%) of 83 participants had adequate immune titres 9 months after the immunisation campaign. Previous vaccination or flavivirus exposure could contribute to this finding. No serious AEFI was found in the 115 participants. In this small series, YF vaccine appeared to be immunogenic with a favourable safety profile in HIV-infected patients on antiretroviral therapy. Higher CD4 cell counts and suppressed HIV-RNA were associated with the presence of an adequate immune titre and higher NTs. Copyright © 2012 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

Expected epidemiological impact of the introduction of a partially effective HIV vaccine among men who have sex with men in Australia.

Science.gov (United States)

Gray, Richard T; Ghaus, Mohammad H; Hoare, Alexander; Wilson, David P

2011-08-18

A trial of the ALVAC-AIDSVAX HIV vaccine was recently found to be partially effective in preventing HIV transmission among study participants in Thailand. The success of this trial means that vaccination may become a viable intervention for the prevention of HIV infection in the medium-term future. Assuming that the vaccine has similar relative protective effectiveness per exposure event for reducing transmission among men who have sex with men (MSM) in high-income settings we investigated the potential population-level impact of rolling out such a vaccine among MSM in New South Wales, Australia. Using a detailed individual-based transmission model that simulates a population of sexually active MSM it was found that one-off intervention of 60% or 30% coverage of a vaccine with characteristics like the ALVAX-AIDSVAX vaccine would likely reduce the cumulative incidence of HIV by 9.6% and 5.1%, respectively, over a 10-year period. Due to the waning of vaccine efficacy, a booster vaccination could be required to maintain this reduction in incidence over the long term. If the previously vaccinated population is given a booster vaccine, with the same protection conferred as with the initial vaccination, every 5 years or every 2 years then the cumulative incidence over 10 years for 60% coverage could be reduced by 14.4% and 22.8%, respectively. Such a weak vaccine, with boosting, may be a potential intervention strategy for the prevention of HIV infection in MSM in high-income countries if further trials show boosting to be safe, acceptable, and cost-effective. However, the moderately low population-level impact suggests that a public health strategy involving such a vaccine should be supplemented with other biomedical and educational strategies. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Barcelona 2002: law, ethics, and human rights. Advancing research and access to HIV vaccines: a framework for action.

Science.gov (United States)

Avrett, Sam

2002-12-01

In light of the continuing spread of HIV infection and the devastating impact of the disease on lives, communities, and economies, particularly in the developing world, the investment in new treatments, vaccines, and microbicides has clearly been inadequate. Efforts must be intensified to develop effective HIV vaccines and to ensure that they are accessible to people in all parts of the world. This article is a summary of a paper by Sam Avrett presented at "Putting Third First: Vaccines, Access to Treatments and the Law," a satellite meeting held at Barcelona on 5 July 2002 and organized by the Canadian HIV/AIDS Legal Network, the AIDS Law Project, South Africa, and the Lawyers Collective HIV/AIDS Unit, India. In the article, Avrett calls for immediate action to increase commitment and funding for HIV vaccines, enhance public support and involvement, accelerate vaccine development, and plan for the eventual delivery of the vaccines. The article briefly outlines steps that governments need to take to implement each of these objectives. The article also provides a menu of potential actions for vaccine advocates to consider as they lobby governments.

Design, implementation, and evaluation at entry of a prospective cohort study of homosexual and bisexual HIV-1-negative men in Belo Horizonte, Brazil: Project Horizonte.

Science.gov (United States)

Carneiro, M; de Figueiredo Antunes, C M; Greco, M; Oliveira, E; Andrade, J; Lignani, L; Greco, D B

2000-10-01

Project Horizonte, an open cohort of homosexual and bisexual HIV-1-negative men, is a component of the Minas Gerais AIDS Vaccine Program of the Federal University of Minas Gerais, Belo Horizonte, Brazil. Its objectives included the evaluation of seroincidence of HIV, to ascertain the role of counseling on behavior modification and to assess their willingness to participate in future HIV vaccine trials. Various means of recruitment were used, including pamphlets, notices in community newspapers, radio, and television, at anonymous testing centers, and by word of mouth. From October 1994 to May 1999, 470 volunteers were enrolled. Their mean age was 26 years and over 70% of them had high school or college education. During the follow-up, they were seen every 6 months, when they received counseling and condoms, and when HIV testing was done. Eighteen seroconversions were observed, and the incidence rates estimates were 1.75 per 100 and 1.99 per 100 person-years, for 36 and 48 months of follow-up, respectively. During the entire period, 139 volunteers were lost to follow-up. Among them, 59 (42.4%) never returned after the initial visit and 51 (36.7) came only once after their initial visit. No losses were observed for those observed during follow-up for more than 3 years. At enrollment, 50% of participants said they would participate in a vaccine trial, and 30% said they might participate. The results obtained up to this moment confirm the feasibility of following this type of cohort for an extended period, estimating HIV incidence rate, and evaluating counseling for safe sexual practices in preparation for clinical trials with candidate HIV vaccines in Brazil.

Basic Research in HIV vaccinology is hampered by reductionist thinking

Directory of Open Access Journals (Sweden)

Marc H V Van Regenmortel

2012-07-01

Full Text Available This review describes the structure-based reverse vaccinology approach aimed at developing vaccine immunogens capable of inducing antibodies that broadly neutralize HIV-1. Some basic principles of protein immunochemistry are reviewed and the implications of the extensive polyspecificity of antibodies for vaccine development are underlined. Although it is natural for investigators to want to know the cause of an effective immunological intervention, the classic notion of causality is shown to have little explanatory value for a system as complex as the immune system, where any observed effect always results from many interactions between a large number of components. Causal explanations are reductive because a single factor is singled out for attention and given undue explanatory weight on its own. Other examples of the negative impact of reductionist thinking on HIV vaccine development are discussed. These include 1 the failure to distinguish between the chemical nature of antigenicity and the biological nature of immunogenicity, 2 the belief that when an HIV-1 epitope is reconstructed by rational design to better fit a neutralizing Mab, this will produce an immunogen able to elicit Abs with the same neutralizing capacity as the Ab used as template for designing the antigen 3 the belief that protection against infection can be analysed at the level of individual molecular interactions although it has meaning only at the level of an entire organism.The numerous unsuccessful strategies that have been used to design HIV-1 vaccine immunogens are described and it is suggested that the convergence of so many negative experimental results, justifies the conclusion that reverse vaccinology is unlikely to lead to the development of a preventive HIV-1 vaccine. Immune correlates of protection in vaccinees have not yet been identified because this will become feasible only retrospectively once an effective vaccine exists.

Abnormal humoral immune response to influenza vaccination in pediatric type-1 human immunodeficiency virus infected patients receiving highly active antiretroviral therapy

Directory of Open Access Journals (Sweden)

Carlos J Montoya

2007-06-01

Full Text Available Given that highly active antiretroviral therapy (HAART has been demonstrated useful to restore immune competence in type-1 human immunodeficiency virus (HIV-1-infected subjects, we evaluated the specific antibody response to influenza vaccine in a cohort of HIV-1-infected children on HAART so as to analyze the quality of this immune response in patients under antiretroviral therapy. Sixteen HIV-1-infected children and 10 HIV-1 seronegative controls were immunized with a commercially available trivalent inactivated influenza vaccine containing the strains A/H1N1, A/H3N2, and B. Serum hemagglutinin inhibition (HI antibody titers were determined for the three viral strains at the time of vaccination and 1 month later. Immunization induced a significantly increased humoral response against the three influenza virus strains in controls, and only against A/H3N2 in HIV-1-infected children. The comparison of post-vaccination HI titers between HIV-1+ patients and HIV-1 negative controls showed significantly higher HI titers against the three strains in controls. In addition, post vaccination protective HI titers (defined as equal to or higher than 1:40 against the strains A/H3N2 and B were observed in a lower proportion of HIV-1+ children than in controls, while a similar proportion of individuals from each group achieved protective HI titers against the A/H1N1 strain. The CD4+ T cell count, CD4/CD8 T cells ratio, and serum viral load were not affected by influenza virus vaccination when pre- vs post-vaccination values were compared. These findings suggest that despite the fact that HAART is efficient in controlling HIV-1 replication and in increasing CD4+ T cell count in HIV-1-infected children, restoration of immune competence and response to cognate antigens remain incomplete, indicating that additional therapeutic strategies are required to achieve a full reconstitution of immune functions.

Selected HIV-1 Env trimeric formulations act as potent immunogens in a rabbit vaccination model.

Directory of Open Access Journals (Sweden)

Leo Heyndrickx

Full Text Available BACKGROUND: Ten to 30% of HIV-1 infected subjects develop broadly neutralizing antibodies (bNAbs during chronic infection. We hypothesized that immunizing rabbits with viral envelope glycoproteins (Envs from these patients may induce bNAbs, when formulated as a trimeric protein and in the presence of an adjuvant. METHODS: Based on in vitro neutralizing activity in serum, patients with bNAbs were selected for cloning of their HIV-1 Env. Seven stable soluble trimeric gp140 proteins were generated from sequences derived from four adults and two children infected with either clade A or B HIV-1. From one of the clade A Envs both the monomeric and trimeric Env were produced for comparison. Rabbits were immunized with soluble gp120 or trimeric gp140 proteins in combination with the adjuvant dimethyl dioctadecyl ammonium/trehalose dibehenate (CAF01. Env binding in rabbit immune serum was determined using ELISAs based on gp120-IIIB protein. Neutralizing activity of IgG purified from rabbit immune sera was measured with the pseudovirus-TZMbl assay and a PBMC-based neutralization assay for selected experiments. RESULTS: It was initially established that gp140 trimers induce better antibody responses over gp120 monomers and that the adjuvant CAF01 was necessary for such strong responses. Gp140 trimers, based on HIV-1 variants from patients with bNAbs, were able to elicit both gp120IIIB specific IgG and NAbs to Tier 1 viruses of different subtypes. Potency of NAbs closely correlated with titers, and an gp120-binding IgG titer above a threshold of 100,000 was predictive of neutralization capability. Finally, peptide inhibition experiments showed that a large fraction of the neutralizing IgG was directed against the gp120 V3 region. CONCLUSIONS: Our results indicate that the strategy of reverse immunology based on selected Env sequences is promising when immunogens are delivered as stabilized trimers in CAF01 adjuvant and that the rabbit is a valuable model

Selected HIV-1 Env trimeric formulations act as potent immunogens in a rabbit vaccination model.

Science.gov (United States)

Heyndrickx, Leo; Stewart-Jones, Guillaume; Jansson, Marianne; Schuitemaker, Hanneke; Bowles, Emma; Buonaguro, Luigi; Grevstad, Berit; Vinner, Lasse; Vereecken, Katleen; Parker, Joe; Ramaswamy, Meghna; Biswas, Priscilla; Vanham, Guido; Scarlatti, Gabriella; Fomsgaard, Anders

2013-01-01

Ten to 30% of HIV-1 infected subjects develop broadly neutralizing antibodies (bNAbs) during chronic infection. We hypothesized that immunizing rabbits with viral envelope glycoproteins (Envs) from these patients may induce bNAbs, when formulated as a trimeric protein and in the presence of an adjuvant. Based on in vitro neutralizing activity in serum, patients with bNAbs were selected for cloning of their HIV-1 Env. Seven stable soluble trimeric gp140 proteins were generated from sequences derived from four adults and two children infected with either clade A or B HIV-1. From one of the clade A Envs both the monomeric and trimeric Env were produced for comparison. Rabbits were immunized with soluble gp120 or trimeric gp140 proteins in combination with the adjuvant dimethyl dioctadecyl ammonium/trehalose dibehenate (CAF01). Env binding in rabbit immune serum was determined using ELISAs based on gp120-IIIB protein. Neutralizing activity of IgG purified from rabbit immune sera was measured with the pseudovirus-TZMbl assay and a PBMC-based neutralization assay for selected experiments. It was initially established that gp140 trimers induce better antibody responses over gp120 monomers and that the adjuvant CAF01 was necessary for such strong responses. Gp140 trimers, based on HIV-1 variants from patients with bNAbs, were able to elicit both gp120IIIB specific IgG and NAbs to Tier 1 viruses of different subtypes. Potency of NAbs closely correlated with titers, and an gp120-binding IgG titer above a threshold of 100,000 was predictive of neutralization capability. Finally, peptide inhibition experiments showed that a large fraction of the neutralizing IgG was directed against the gp120 V3 region. Our results indicate that the strategy of reverse immunology based on selected Env sequences is promising when immunogens are delivered as stabilized trimers in CAF01 adjuvant and that the rabbit is a valuable model for HIV vaccine studies.

Constitutively Active MAVS Inhibits HIV-1 Replication via Type I Interferon Secretion and Induction of HIV-1 Restriction Factors.

Directory of Open Access Journals (Sweden)

Sachin Gupta

Full Text Available Type I interferon is known to inhibit HIV-1 replication through the induction of interferon stimulated genes (ISG, including a number of HIV-1 restriction factors. To better understand interferon-mediated HIV-1 restriction, we constructed a constitutively active form of the RIG-I adapter protein MAVS. Constitutive MAVS was generated by fusion of full length MAVS to a truncated form of the Epstein Barr virus protein LMP1 (ΔLMP1. Supernatant from ΔLMP1-MAVS-transfected 293T cells contained high levels of type I interferons and inhibited HIV replication in both TZM-bl and primary human CD4+ T cells. Supernatant from ΔLMP1-MAVS-transfected 293T cells also inhibited replication of VSV-G pseudotyped single cycle SIV in TZM-bl cells, suggesting restriction was post-entry and common to both HIV and SIV. Gene array analysis of ΔLMP1-MAVS-transfected 293T cells and trans-activated CD4+ T cells showed significant upregulation of ISG, including previously characterized HIV restriction factors Viperin, Tetherin, MxB, and ISG56. Interferon blockade studies implicated interferon-beta in this response. In addition to direct viral inhibition, ΔLMP1-MAVS markedly enhanced secretion of IFN-β and IL-12p70 by dendritic cells and the activation and maturation of dendritic cells. Based on this immunostimulatory activity, an adenoviral vector (Ad5 expressing ΔLMP1-MAVS was tested as a molecular adjuvant in an HIV vaccine mouse model. Ad5-Gag antigen combined with Ad5-ΔLMP1-MAVS enhanced control of vaccinia-gag replication in a mouse challenge model, with 4/5 animals showing undetectable virus following challenge. Overall, ΔLMP1-MAVS is a promising reagent to inhibit HIV-1 replication in infected tissues and enhance vaccine-mediated immune responses, while avoiding toxicity associated with systemic type I interferon administration.

Socio-behaviour challenges to phase III HIV vaccine trials in Sub ...

African Journals Online (AJOL)

Abstract. Background: A number of countries in sub-Saharan Africa are preparing for HIV vaccine efficacy trials. Social and behavioural factors related to HIV transmission require examination in each setting where these trials are considered. As part of this, several countries have also recently begun preparatory research ...

DNA/MVA Vaccination of HIV-1 Infected Participants with Viral Suppression on Antiretroviral Therapy, followed by Treatment Interruption: Elicitation of Immune Responses without Control of Re-Emergent Virus.

Directory of Open Access Journals (Sweden)

Melanie Thompson

Full Text Available GV-TH-01, a Phase 1 open-label trial of a DNA prime—Modified Vaccinia Ankara (MVA boost vaccine (GOVX-B11, was undertaken in HIV infected participants on antiretroviral treatment (ART to evaluate safety and vaccine-elicited T cell responses, and explore the ability of elicited CD8+ T cells to control viral rebound during analytical treatment interruption (TI. Nine men who began antiretroviral therapy (ART within 18 months of seroconversion and had sustained plasma HIV-1 RNA <50 copies/mL for at least 6 months were enrolled. Median age was 38 years, median pre-ART HIV-1 RNA was 140,000 copies/ml and mean baseline CD4 count was 755/μl. Two DNA, followed by 2 MVA, inoculations were given 8 weeks apart. Eight subjects completed all vaccinations and TI. Clinical and laboratory adverse events were generally mild, with no serious or grade 4 events. Only reactogenicity events were considered related to study drug. No treatment emergent viral resistance was seen. The vaccinations did not reduce viral reservoirs and virus re-emerged in all participants during TI, with a median time to re-emergence of 4 weeks. Eight of 9 participants had CD8+ T cells that could be stimulated by vaccine-matched Gag peptides prior to vaccination. Vaccinations boosted these responses as well as eliciting previously undetected CD8+ responses. Elicited T cells did not display signs of exhaustion. During TI, temporal patterns of viral re-emergence and Gag-specific CD8+ T cell expansion suggested that vaccine-specific CD8+ T cells had been stimulated by re-emergent virus in only 2 of 8 participants. In these 2, transient decreases in viremia were associated with Gag selection in known CD8+ T cell epitopes. We hypothesize that escape mutations, already archived in the viral reservoir, plus a poor ability of CD8+ T cells to traffic to and control virus at sites of re-emergence, limited the therapeutic efficacy of the DNA/MVA vaccine.clinicaltrials.gov NCT01378156.

DNA/MVA Vaccination of HIV-1 Infected Participants with Viral Suppression on Antiretroviral Therapy, followed by Treatment Interruption: Elicitation of Immune Responses without Control of Re-Emergent Virus.

Science.gov (United States)

Thompson, Melanie; Heath, Sonya L; Sweeton, Bentley; Williams, Kathy; Cunningham, Pamela; Keele, Brandon F; Sen, Sharon; Palmer, Brent E; Chomont, Nicolas; Xu, Yongxian; Basu, Rahul; Hellerstein, Michael S; Kwa, Suefen; Robinson, Harriet L

2016-01-01

GV-TH-01, a Phase 1 open-label trial of a DNA prime—Modified Vaccinia Ankara (MVA) boost vaccine (GOVX-B11), was undertaken in HIV infected participants on antiretroviral treatment (ART) to evaluate safety and vaccine-elicited T cell responses, and explore the ability of elicited CD8+ T cells to control viral rebound during analytical treatment interruption (TI). Nine men who began antiretroviral therapy (ART) within 18 months of seroconversion and had sustained plasma HIV-1 RNA HIV-1 RNA was 140,000 copies/ml and mean baseline CD4 count was 755/μl. Two DNA, followed by 2 MVA, inoculations were given 8 weeks apart. Eight subjects completed all vaccinations and TI. Clinical and laboratory adverse events were generally mild, with no serious or grade 4 events. Only reactogenicity events were considered related to study drug. No treatment emergent viral resistance was seen. The vaccinations did not reduce viral reservoirs and virus re-emerged in all participants during TI, with a median time to re-emergence of 4 weeks. Eight of 9 participants had CD8+ T cells that could be stimulated by vaccine-matched Gag peptides prior to vaccination. Vaccinations boosted these responses as well as eliciting previously undetected CD8+ responses. Elicited T cells did not display signs of exhaustion. During TI, temporal patterns of viral re-emergence and Gag-specific CD8+ T cell expansion suggested that vaccine-specific CD8+ T cells had been stimulated by re-emergent virus in only 2 of 8 participants. In these 2, transient decreases in viremia were associated with Gag selection in known CD8+ T cell epitopes. We hypothesize that escape mutations, already archived in the viral reservoir, plus a poor ability of CD8+ T cells to traffic to and control virus at sites of re-emergence, limited the therapeutic efficacy of the DNA/MVA vaccine. clinicaltrials.gov NCT01378156.

Desarrollo de vacunas contra el virus de la inmunodeficiencia humana tipo 1: Relevancia de la inmunidad celular contra subtipos Development of vaccines for HIV-1: Relevance of subtype-specific cellular immunity

Directory of Open Access Journals (Sweden)

Ana María Rodríguez

2010-12-01

Full Text Available Han pasado casi 30 años de la detección de los primeros casos de infección con HIV-1 y aún no se ha conseguido desarrollar una vacuna efectiva y segura. A pesar del impacto positivo sobre la pandemia que se ha conseguido gracias a los avances en la terapia antirretroviral (TARV, el HIV/sida sigue constituyendo un grave problema para la salud pública, especialmente en los países en desarrollo, donde es difícil el acceso al tratamiento. En el mundo, 33 millones de personas viven con el virus del sida, mientras que en la Argentina se calcula que habría unos 120 000 infectados. Uno de los desafíos para lograr una vacuna contra el HIV es la variabilidad viral. El grupo M, responsable de la pandemia, se encuentra dividido en 10 subtipos y varios sub-subtipos, además de las 48 formas recombinantes circulantes y más de cien formas recombinantes únicas. La epidemia de HIV en nuestro país es tan compleja como en el resto del mundo, con la co-circulación principalmente de virus pertenecientes al subtipo B y recombinantes BF (CRF12_BF y derivadas. A pesar de la cantidad de trabajos dedicados a la caracterización de la respuesta inmune y al desarrollo de vacunas, no queda claro cuál es el impacto de la variabilidad en la elección del antígeno. Trabajos realizados en nuestro laboratorio demuestran el papel que juega la inmunidad celular con respecto a las variantes recombinantes BF, tanto en humanos como en modelos animales. Estos resultados son de importancia en el desarrollo de futuras vacunas para nuestra región.It has been almost 30 years since the detection of the first HIV-1 cases and yet an effective and safe vaccine has not been developed. Although, advances in antiretroviral therapy (HAART have produced a major impact on the pandemic, and even though HIV/aids remains a major concern for developing countries, where access to therapy is limited. The last report from UNAIDS notified 33 million people living with HIV/aids, worldwide

Safety and pharmacokinetics of the Fc-modified HIV-1 human monoclonal antibody VRC01LS: A Phase 1 open-label clinical trial in healthy adults

OpenAIRE

Gaudinski, Martin R.; Coates, Emily E.; Houser, Katherine V.; Chen, Grace L.; Yamshchikov, Galina; Saunders, Jamie G.; Holman, LaSonji A.; Gordon, Ingelise; Plummer, Sarah; Hendel, Cynthia S.; Conan-Cibotti, Michelle; Lorenzo, Margarita Gomez; Sitar, Sandra; Carlton, Kevin; Laurencot, Carolyn

2018-01-01

Background VRC01 is a human broadly neutralizing monoclonal antibody (bnMAb) against the CD4-binding site of the HIV-1 envelope glycoprotein (Env) that is currently being evaluated in a Phase IIb adult HIV-1 prevention efficacy trial. VRC01LS is a modified version of VRC01, designed for extended serum half-life by increased binding affinity to the neonatal Fc receptor. Methods and findings This Phase I dose-escalation study of VRC01LS in HIV-negative healthy adults was conducted by the Vaccin...

HIV-DNA Given with or without Intradermal Electroporation Is Safe and Highly Immunogenic in Healthy Swedish HIV-1 DNA/MVA Vaccinees: A Phase I Randomized Trial.

Directory of Open Access Journals (Sweden)

Charlotta Nilsson

Full Text Available We compared safety and immunogenicity of intradermal (ID vaccination with and without electroporation (EP in a phase I randomized placebo-controlled trial of an HIV-DNA prime HIV-MVA boost vaccine in healthy Swedish volunteers.HIV-DNA plasmids encoding HIV-1 genes gp160 subtypes A, B and C; Rev B; Gag A and B and RTmut B were given ID at weeks 0, 6 and 12 in a dose of 0.6 mg. Twenty-five volunteers received vaccine using a needle-free device (ZetaJet with (n=16 or without (n=9 ID EP (Dermavax. Five volunteers were placebo recipients. Boosting with recombinant MVA-CMDR expressing HIV-1 Env, Gag, Pol of CRF01_AE (HIV-MVA or placebo was performed at weeks 24 and 40. Nine of the vaccinees received a subtype C CN54 gp140 protein boost together with HIV-MVA.The ID/EP delivery was very well tolerated. After three HIV-DNA immunizations, no statistically significant difference was seen in the IFN-γ ELISpot response rate to Gag between HIV-DNA ID/EP recipients (5/15, 33% and HIV-DNA ID recipients (1/7, 14%, p=0.6158. The first HIV-MVA or HIV-MVA+gp140 vaccination increased the IFN-γ ELISpot response rate to 18/19 (95%. CD4+ and/or CD8+ T cell responses to Gag or Env were demonstrable in 94% of vaccinees. A balanced CD4+ and CD8+ T cell response was noted, with 78% and 71% responders, respectively. IFN-γ and IL-2 dominated the CD4+ T cell response to Gag and Env. The CD8+ response to Gag was broader with expression of IFN-γ, IL-2, MIP-1β and/or CD107. No differences were seen between DNA vaccine groups. Binding antibodies were induced after the second HIV-MVA+/-gp140 in 93% of vaccinees to subtype C Env, with the highest titers among EP/gp140 recipients.Intradermal electroporation of HIV-DNA was well tolerated. Strong cell- and antibody-mediated immune responses were elicited by the HIV-DNA prime and HIV-MVA boosting regimen, with or without intradermal electroporation use.International Standard Randomised Controlled Trial Number (ISRCTN 60284968.

HIV-DNA Given with or without Intradermal Electroporation Is Safe and Highly Immunogenic in Healthy Swedish HIV-1 DNA/MVA Vaccinees: A Phase I Randomized Trial.

Science.gov (United States)

Nilsson, Charlotta; Hejdeman, Bo; Godoy-Ramirez, Karina; Tecleab, Teghesti; Scarlatti, Gabriella; Bråve, Andreas; Earl, Patricia L; Stout, Richard R; Robb, Merlin L; Shattock, Robin J; Biberfeld, Gunnel; Sandström, Eric; Wahren, Britta

2015-01-01

We compared safety and immunogenicity of intradermal (ID) vaccination with and without electroporation (EP) in a phase I randomized placebo-controlled trial of an HIV-DNA prime HIV-MVA boost vaccine in healthy Swedish volunteers. HIV-DNA plasmids encoding HIV-1 genes gp160 subtypes A, B and C; Rev B; Gag A and B and RTmut B were given ID at weeks 0, 6 and 12 in a dose of 0.6 mg. Twenty-five volunteers received vaccine using a needle-free device (ZetaJet) with (n=16) or without (n=9) ID EP (Dermavax). Five volunteers were placebo recipients. Boosting with recombinant MVA-CMDR expressing HIV-1 Env, Gag, Pol of CRF01_AE (HIV-MVA) or placebo was performed at weeks 24 and 40. Nine of the vaccinees received a subtype C CN54 gp140 protein boost together with HIV-MVA. The ID/EP delivery was very well tolerated. After three HIV-DNA immunizations, no statistically significant difference was seen in the IFN-γ ELISpot response rate to Gag between HIV-DNA ID/EP recipients (5/15, 33%) and HIV-DNA ID recipients (1/7, 14%, p=0.6158). The first HIV-MVA or HIV-MVA+gp140 vaccination increased the IFN-γ ELISpot response rate to 18/19 (95%). CD4+ and/or CD8+ T cell responses to Gag or Env were demonstrable in 94% of vaccinees. A balanced CD4+ and CD8+ T cell response was noted, with 78% and 71% responders, respectively. IFN-γ and IL-2 dominated the CD4+ T cell response to Gag and Env. The CD8+ response to Gag was broader with expression of IFN-γ, IL-2, MIP-1β and/or CD107. No differences were seen between DNA vaccine groups. Binding antibodies were induced after the second HIV-MVA+/-gp140 in 93% of vaccinees to subtype C Env, with the highest titers among EP/gp140 recipients. Intradermal electroporation of HIV-DNA was well tolerated. Strong cell- and antibody-mediated immune responses were elicited by the HIV-DNA prime and HIV-MVA boosting regimen, with or without intradermal electroporation use. International Standard Randomised Controlled Trial Number (ISRCTN) 60284968.

Perturbation of B Cell Gene Expression Persists in HIV-Infected Children Despite Effective Antiretroviral Therapy and Predicts H1N1 Response.

Science.gov (United States)

Cotugno, Nicola; De Armas, Lesley; Pallikkuth, Suresh; Rinaldi, Stefano; Issac, Biju; Cagigi, Alberto; Rossi, Paolo; Palma, Paolo; Pahwa, Savita

2017-01-01

Despite effective antiretroviral therapy (ART), HIV-infected individuals with apparently similar clinical and immunological characteristics can vary in responsiveness to vaccinations. However, molecular mechanisms responsible for such impairment, as well as biomarkers able to predict vaccine responsiveness in HIV-infected children, remain unknown. Following the hypothesis that a B cell qualitative impairment persists in HIV-infected children (HIV) despite effective ART and phenotypic B cell immune reconstitution, the aim of the current study was to investigate B cell gene expression of HIV compared to age-matched healthy controls (HCs) and to determine whether distinct gene expression patterns could predict the ability to respond to influenza vaccine. To do so, we analyzed prevaccination transcriptional levels of a 96-gene panel in equal numbers of sort-purified B cell subsets (SPBS) isolated from peripheral blood mononuclear cells using multiplexed RT-PCR. Immune responses to H1N1 antigen were determined by hemaglutination inhibition and memory B cell ELISpot assays following trivalent-inactivated influenza vaccination (TIV) for all study participants. Although there were no differences in terms of cell frequencies of SPBS between HIV and HC, the groups were distinguishable based upon gene expression analyses. Indeed, a 28-gene signature, characterized by higher expression of genes involved in the inflammatory response and immune activation was observed in activated memory B cells (CD27 + CD21 - ) from HIV when compared to HC despite long-term viral control (>24 months). Further analysis, taking into account H1N1 responses after TIV in HIV participants, revealed that a 25-gene signature in resting memory (RM) B cells (CD27 + CD21 + ) was able to distinguish vaccine responders from non-responders (NR). In fact, prevaccination RM B cells of responders showed a higher expression of gene sets involved in B cell adaptive immune responses ( APRIL, BTK, BLIMP1 ) and

Preclinical assessment of HIV vaccines and microbicides by repeated low-dose virus challenges.

Directory of Open Access Journals (Sweden)

Roland R Regoes

2005-08-01

Full Text Available Trials in macaque models play an essential role in the evaluation of biomedical interventions that aim to prevent HIV infection, such as vaccines, microbicides, and systemic chemoprophylaxis. These trials are usually conducted with very high virus challenge doses that result in infection with certainty. However, these high challenge doses do not realistically reflect the low probability of HIV transmission in humans, and thus may rule out preventive interventions that could protect against "real life" exposures. The belief that experiments involving realistically low challenge doses require large numbers of animals has so far prevented the development of alternatives to using high challenge doses.Using statistical power analysis, we investigate how many animals would be needed to conduct preclinical trials using low virus challenge doses. We show that experimental designs in which animals are repeatedly challenged with low doses do not require unfeasibly large numbers of animals to assess vaccine or microbicide success.Preclinical trials using repeated low-dose challenges represent a promising alternative approach to identify potential preventive interventions.

Altered response hierarchy and increased T-cell breadth upon HIV-1 conserved element DNA vaccination in macaques.

Directory of Open Access Journals (Sweden)

Viraj Kulkarni

Full Text Available HIV sequence diversity and potential decoy epitopes are hurdles in the development of an effective AIDS vaccine. A DNA vaccine candidate comprising of highly conserved p24(gag elements (CE induced robust immunity in all 10 vaccinated macaques, whereas full-length gag DNA vaccination elicited responses to these conserved elements in only 5 of 11 animals, targeting fewer CE per animal. Importantly, boosting CE-primed macaques with DNA expressing full-length p55(gag increased both magnitude of CE responses and breadth of Gag immunity, demonstrating alteration of the hierarchy of epitope recognition in the presence of pre-existing CE-specific responses. Inclusion of a conserved element immunogen provides a novel and effective strategy to broaden responses against highly diverse pathogens by avoiding decoy epitopes, while focusing responses to critical viral elements for which few escape pathways exist.

Structure-Based Design of Novel HIV-1 Protease Inhibitors to Combat Drug Resistance

Energy Technology Data Exchange (ETDEWEB)

Ghosh,A.; Sridhar, P.; Leshchenko, S.; Hussain, A.; Li, J.; Kovalevsky, A.; Walters, D.; Wedelind, J.; Grum-Tokars, V.; et al.

2006-01-01

Structure-based design and synthesis of novel HIV protease inhibitors are described. The inhibitors are designed specifically to interact with the backbone of HIV protease active site to combat drug resistance. Inhibitor 3 has exhibited exceedingly potent enzyme inhibitory and antiviral potency. Furthermore, this inhibitor maintains impressive potency against a wide spectrum of HIV including a variety of multi-PI-resistant clinical strains. The inhibitors incorporated a stereochemically defined 5-hexahydrocyclopenta[b]furanyl urethane as the P2-ligand into the (R)-(hydroxyethylamino)sulfonamide isostere. Optically active (3aS,5R,6aR)-5-hydroxy-hexahydrocyclopenta[b]furan was prepared by an enzymatic asymmetrization of meso-diacetate with acetyl cholinesterase, radical cyclization, and Lewis acid-catalyzed anomeric reduction as the key steps. A protein-ligand X-ray crystal structure of inhibitor 3-bound HIV-1 protease (1.35 Angstroms resolution) revealed extensive interactions in the HIV protease active site including strong hydrogen bonding interactions with the backbone. This design strategy may lead to novel inhibitors that can combat drug resistance.

HIV-1 Env DNA vaccine plus protein boost delivered by EP expands B- and T-cell responses and neutralizing phenotype in vivo.

Directory of Open Access Journals (Sweden)

Kar Muthumani

Full Text Available An effective HIV vaccine will most likely require the induction of strong T-cell responses, broadly neutralizing antibodies (bNAbs, and the elicitation of antibody-dependent cellular cytotoxicity (ADCC. Previously, we demonstrated the induction of strong HIV/SIV cellular immune responses in macaques and humans using synthetic consensus DNA immunogens delivered via adaptive electroporation (EP. However, the ability of this improved DNA approach to prime for relevant antibody responses has not been previously studied. Here, we investigate the immunogenicity of consensus DNA constructs encoding gp140 sequences from HIV-1 subtypes A, B, C and D in a DNA prime-protein boost vaccine regimen. Mice and guinea pigs were primed with single- and multi-clade DNA via EP and boosted with recombinant gp120 protein. Sera were analyzed for gp120 binding and induction of neutralizing antibody activity. Immunization with recombinant Env protein alone induced low-titer binding antibodies with limited neutralization breath. In contrast, the synthetic DNA prime-protein boost protocol induced significantly higher antibody binding titers. Furthermore, sera from DNA prime-protein boost groups were able to neutralize a broader range of viruses in a panel of tier 1 clade B viruses as well as multiple tier 1 clade A and clade C viruses. Further investigation of synthetic DNA prime plus adaptive EP plus protein boost appears warranted.

Sexual behavior, risk perception, and HIV transmission can respond to HIV antiviral drugs and vaccines through multiple pathways

OpenAIRE

Stephen Tully; Monica Cojocaru; Chris T. Bauch

2015-01-01

There has been growing use of highly active antiretroviral treatment (HAART) for HIV and significant progress in developing prophylactic HIV vaccines. The simplest theories of counterproductive behavioral responses to such interventions tend to focus on single feedback mechanisms: for instance, HAART optimism makes infection less scary and thus promotes risky sexual behavior. Here, we develop an agent based, age-structured model of HIV transmission, risk perception, and partner selection in a...

A mammalian cell based FACS-panning platform for the selection of HIV-1 envelopes for vaccine development.